Is it possible to capture or print what&#39;s displayed in an html canvas as an image or pdf? 

I&#39;d like to generate an image via canvas, and be able to generate a png from that image.

Capture HTML Canvas as gif/jpg/png/pdf?

Given a transparent PNG displaying a simple shape in white, is it possible to somehow change the color of this through CSS? Some kind of overlay or what not?


Change color of PNG image via CSS?

When should certain image file types be used when building websites or interfaces, etc?

What are their points of strength and weakness?

I know that PNG &amp; GIF are lossless, while JPEG is lossy.  
But what is the main difference between PNG &amp; GIF?  
Why should I prefer one over the other?
What is SVG and when should I use it?

If you don&#39;t care about each and every pixel, should you always use JPEG since it&#39;s the &quot;lightest&quot; one?

What are the different usecases of PNG vs. GIF vs. JPEG vs. SVG?

I have a SVG file that has a defined size of 16x16. When I use ImageMagick&#39;s convert program to convert it into a PNG, then I get a 16x16 pixel PNG which is way too small:

    convert test.svg test.png

I need to specify the pixel size of the output PNG. `-size` parameter seems to be ignored, `-scale` parameter scales the PNG **after** it has been converted to PNG. The best result up to now I got by using the `-density` parameter:

    convert -density 1200 test.svg test.png

But I&#39;m not satisfied, because I want to specify the output size in pixels without doing math to calculate the density value. So I want to do something like this:

    convert -setTheOutputSizeOfThePng 1024x1024 test.svg test.png

So what is the magic parameter I have to use here? 

How to convert a SVG to a PNG with ImageMagick?

Other than the fact that PNG is a more common image format, is there any technical reason to favor favicon.png vs. favicon.ico?

I&#39;m supporting modern browsers which all support PNG favorite icons.

favicon.png vs favicon.ico - why should I use PNG instead of ICO?

I&#39;ve got some PNG images with transparency, and I need to create versions with the image layer composed onto a white background.  I&#39;ve tried various things with Image Magick &quot;convert&quot; operations, but either nothing happens at all or I get an error.  I don&#39;t want to go to an intermediate JPG form because I don&#39;t want the artifacts.  Of course it&#39;s easy to do this in Gimp or Photoshop or whatever, but I&#39;d really rather script it from the command line because there  are many of these things.

An example of a non-working Image Magick command is:

    convert img1.png -background white -flatten img1-white.png

That results in an error.

Thanks!

Replace transparency in PNG images with white background

In a HTML5 document, which favicon format do you recommend and why? I want it to be supported by IE7 and all the modern browsers.

Also, when using .png, do I need to specify the type (type=&quot;image/png&quot;)?
    &lt;link rel=&quot;icon&quot; type=&quot;image/png&quot; href=&quot;image.png&quot; /&gt;

Favicon: .ico or .png / correct tags?

How to convert a PNG image to a SVG?

I have a PNG image, that has free form (non square).

I need to apply drop-shadow effect to this image.

The standard approach ...

&lt;!-- language: lang-css --&gt;

    -o-box-shadow:      12px 12px 29px #555;
    -icab-box-shadow:   12px 12px 29px #555;
    -khtml-box-shadow:  12px 12px 29px #555;
    -moz-box-shadow:    12px 12px 29px #555;
    -webkit-box-shadow: 12px 12px 29px #555;
    box-shadow:         12px 12px 29px #555;
... displays shadows for this image, like it is a square. So, I see my image and square shadow, that doesn&#39;t follows the form of object, displayed in image.

Is there any way to do it properly?

Drop shadow for PNG image in CSS

I have a full screen PNG I want to display on splash. Only one error there, and I have no idea
what size to put in every drawable folder (`ldpi`, `mdpi`, `hdpi`, and `xhdpi`). My application is supposed to run good and beautiful on all phones and tablets. What sizes (in pixels) should I create so the splash displays nice on all screens?


Android splash screen image sizes to fit all devices

I&#39;m trying to save a `UIImage` to `NSData` and then read the `NSData` back to a new `UIImage` in Swift. To convert the `UIImage` to `NSData` I&#39;m using the following code: 
    
    let imageData: NSData = UIImagePNGRepresentation(myImage)

How do I convert `imageData` (i.e., `NSData`) back to a new `UIImage`?

 

Convert UIImage to NSData and convert back to UIImage in Swift?

What favicon dimensions, file formats and meta/link tags should be used as of 2022? This includes apple icon, windows, android and other devices people use today.

I use Opera and I can see it supports svg format. Is it the best solution to use svg nowadays? Is there any option &quot;one file fits all&quot;?

I&#39;ve been browsing many websites and checked different &quot;favicon generators&quot;. All of them are years old and work mostly with png files.

**For example:**
What code should be used for ico and svg? 

    &lt;link rel=&quot;icon&quot; href=&quot;favicon.ico&quot; type=&quot;image/ico&quot;&gt;
    &lt;link rel=&quot;icon&quot; href=&quot;favicon.svg&quot; type=&quot;image/svg+xml&quot;&gt;



or should dimensions be specified if ico contains more sizes? I didn&#39;t find one good answer.

    &lt;link rel=&quot;icon&quot; sizes=&quot;16x16 24x24 32x32 48x48 64x64&quot; href=&quot;favicon.ico&quot;&gt;


Please provide dimensions, file formats and meta/link tags of what favicons should be used.



Favicon Standard - 2022 - svg, ico, png and dimensions?

Suppose you have any image (PNG or JPG).
This image has a white background and I need to make this background transparent.

I have tried with these examples:

 - `convert original.png -background none transparent.png`
 - `convert original.png -background white -flatten -alpha off transparent.png`

but with no desirable results.

How can I make it?

IMPORTANT: Using `convert` command-line.

Set transparent background using ImageMagick and commandline prompt

I&#39;m using PIL to convert a transparent PNG image uploaded with Django to a JPG file. The output looks broken.

###Source file

![transparent source file][1]

###Code

    Image.open(object.logo.path).save(&#39;/tmp/output.jpg&#39;, &#39;JPEG&#39;)

or

    Image.open(object.logo.path).convert(&#39;RGB&#39;).save(&#39;/tmp/output.png&#39;)

###Result

Both ways, the resulting image looks like this:

![resulting file][2]

Is there a way to fix this? I&#39;d like to have white background where the transparent background used to be.


----------

# Solution

Thanks to the great answers, I&#39;ve come up with the following function collection:

    import Image
    import numpy as np


    def alpha_to_color(image, color=(255, 255, 255)):
        &quot;&quot;&quot;Set all fully transparent pixels of an RGBA image to the specified color.
        This is a very simple solution that might leave over some ugly edges, due
        to semi-transparent areas. You should use alpha_composite_with color instead.

        Source: http://stackoverflow.com/a/9166671/284318

        Keyword Arguments:
        image -- PIL RGBA Image object
        color -- Tuple r, g, b (default 255, 255, 255)

        &quot;&quot;&quot; 
        x = np.array(image)
        r, g, b, a = np.rollaxis(x, axis=-1)
        r[a == 0] = color[0]
        g[a == 0] = color[1]
        b[a == 0] = color[2] 
        x = np.dstack([r, g, b, a])
        return Image.fromarray(x, &#39;RGBA&#39;)


    def alpha_composite(front, back):
        &quot;&quot;&quot;Alpha composite two RGBA images.

        Source: http://stackoverflow.com/a/9166671/284318

        Keyword Arguments:
        front -- PIL RGBA Image object
        back -- PIL RGBA Image object

        &quot;&quot;&quot;
        front = np.asarray(front)
        back = np.asarray(back)
        result = np.empty(front.shape, dtype=&#39;float&#39;)
        alpha = np.index_exp[:, :, 3:]
        rgb = np.index_exp[:, :, :3]
        falpha = front[alpha] / 255.0
        balpha = back[alpha] / 255.0
        result[alpha] = falpha + balpha * (1 - falpha)
        old_setting = np.seterr(invalid=&#39;ignore&#39;)
        result[rgb] = (front[rgb] * falpha + back[rgb] * balpha * (1 - falpha)) / result[alpha]
        np.seterr(**old_setting)
        result[alpha] *= 255
        np.clip(result, 0, 255)
        # astype(&#39;uint8&#39;) maps np.nan and np.inf to 0
        result = result.astype(&#39;uint8&#39;)
        result = Image.fromarray(result, &#39;RGBA&#39;)
        return result


    def alpha_composite_with_color(image, color=(255, 255, 255)):
        &quot;&quot;&quot;Alpha composite an RGBA image with a single color image of the
        specified color and the same size as the original image.

        Keyword Arguments:
        image -- PIL RGBA Image object
        color -- Tuple r, g, b (default 255, 255, 255)

        &quot;&quot;&quot;
        back = Image.new(&#39;RGBA&#39;, size=image.size, color=color + (255,))
        return alpha_composite(image, back)

    
    def pure_pil_alpha_to_color_v1(image, color=(255, 255, 255)):
        &quot;&quot;&quot;Alpha composite an RGBA Image with a specified color.

        NOTE: This version is much slower than the
        alpha_composite_with_color solution. Use it only if
        numpy is not available.

        Source: http://stackoverflow.com/a/9168169/284318

        Keyword Arguments:
        image -- PIL RGBA Image object
        color -- Tuple r, g, b (default 255, 255, 255)

        &quot;&quot;&quot; 
        def blend_value(back, front, a):
            return (front * a + back * (255 - a)) / 255
        
        def blend_rgba(back, front):
            result = [blend_value(back[i], front[i], front[3]) for i in (0, 1, 2)]
            return tuple(result + [255])
        
        im = image.copy()  # don&#39;t edit the reference directly
        p = im.load()  # load pixel array
        for y in range(im.size[1]):
            for x in range(im.size[0]):
                p[x, y] = blend_rgba(color + (255,), p[x, y])
        
        return im

    def pure_pil_alpha_to_color_v2(image, color=(255, 255, 255)):
        &quot;&quot;&quot;Alpha composite an RGBA Image with a specified color.

        Simpler, faster version than the solutions above.

        Source: http://stackoverflow.com/a/9459208/284318

        Keyword Arguments:
        image -- PIL RGBA Image object
        color -- Tuple r, g, b (default 255, 255, 255)

        &quot;&quot;&quot;
        image.load()  # needed for split()
        background = Image.new(&#39;RGB&#39;, image.size, color)
        background.paste(image, mask=image.split()[3])  # 3 is the alpha channel
        return background


## Performance

The simple non-compositing `alpha_to_color` function is the fastest solution, but leaves behind ugly borders because it does not handle semi transparent areas.

Both the pure PIL and the numpy compositing solutions give great results, but `alpha_composite_with_color` is much faster (8.93 msec) than `pure_pil_alpha_to_color` (79.6 msec). &lt;del&gt;If numpy is available on your system, that&#39;s the way to go.&lt;/del&gt; (Update: The new pure PIL version is the fastest of all mentioned solutions.)

    $ python -m timeit &quot;import Image; from apps.front import utils; i = Image.open(u&#39;logo.png&#39;); i2 = utils.alpha_to_color(i)&quot;
    10 loops, best of 3: 4.67 msec per loop
    $ python -m timeit &quot;import Image; from apps.front import utils; i = Image.open(u&#39;logo.png&#39;); i2 = utils.alpha_composite_with_color(i)&quot;
    10 loops, best of 3: 8.93 msec per loop
    $ python -m timeit &quot;import Image; from apps.front import utils; i = Image.open(u&#39;logo.png&#39;); i2 = utils.pure_pil_alpha_to_color(i)&quot;
    10 loops, best of 3: 79.6 msec per loop
    $ python -m timeit &quot;import Image; from apps.front import utils; i = Image.open(u&#39;logo.png&#39;); i2 = utils.pure_pil_alpha_to_color_v2(i)&quot;
    10 loops, best of 3: 1.1 msec per loop


  [1]: http://i.stack.imgur.com/I2uNe.png
  [2]: http://i.stack.imgur.com/rmlPz.png

Convert RGBA PNG to RGB with PIL

I was wondering if PNG contains data like the following?

What I did was to convert the jpg file to png format, and I was expecting to retrieve the same info I had on the jpg as below:

*Currently using this [as3 library][1] to read the data.*

- IDF0--- IDF @[134 - 248] (9 entries)
 - Orientation (SHORT) : 1 	
 - XResolution (RATIONAL) : 72/1 	
 - YResolution (RATIONAL) : 72/1
 - ResolutionUnit (SHORT) : 2 	
 - Software (ASCIIx16) : QuickTime 7.6.6 	
 - DateTime (ASCIIx20)  : 2011:10:02 22:43:37 	
 - HostComputer (ASCIIx16)  : Mac OS X 10.6.8
 - Exif IFD (LONG) : 8  34853	
 - GPS IFD (LONG) : 248

&amp;nbsp;

- EXIF IDF--- IDF @[8 - 134](10 entries)
 - ExifVersion (UNDEFINEDx4) : 0220
 - DateTimeOrigina (ASCIIx20)  : 2011:04:14 17:22:01
 - UserComment (UNDEFINEDx63)  : ASCII
 - FlashpixVersion (UNDEFINEDx4) : 0100
 - ColorSpace (SHORT) : 1
 - PixelXDimension (LONG) : 1022
 - PixelYDimension (LONG) : 486
 - Unknown (ASCIIx13)  : Image Tag-LOL
 - SceneCaptureType (SHORT) : 0

&amp;nbsp;

- GPS IDF--- IDF @[248 - 338](7 entries)
 - Interoperability Index (ASCIIx2) : N
 - Interoperability Version (RATIONALx3)  @425: 52/1, 1144/100, 0/1
 - Unknown (ASCIIx2) : W
 - Unknown (RATIONALx3)  : 1/1, 4392/100, 0/1
 - Unknown (RATIONAL)  : 5/1
 - Unknown (ASCIIx2) : T
 - Unknown (RATIONAL)  : 3694/117

&amp;nbsp;

  [1]: http://code.google.com/p/as3-xmp-file/

Does PNG contain EXIF data like JPG?

Just ran my site in chrome and suprisingly it comes up with this warning for each of my .png images:

    Resource interpreted as image but transferred with MIME type application/octet-stream.

Anyone seen this before?

Regards

MIME type warning in chrome for png images

How can I merge several `.png` files into one PDF file in Unix?

Merging png images into one pdf file

I&#39;ve been trying to convert SVG images to PNG using C#, without having to write too much code. Can anyone recommend a library or example code for doing this?

Converting SVG to PNG using C#

The following PHP code snippet uses GD to resize a browser-uploaded PNG to 128x128. It works great, except that the transparent areas in the original image are being replaced with a solid color- black in my case. 

Even though `imagesavealpha` is set, something isn&#39;t quite right.

What&#39;s the best way to preserve the transparency in the resampled image?
    
    $uploadTempFile = $myField[ &#39;tmp_name&#39; ]
    list( $uploadWidth, $uploadHeight, $uploadType ) 
      = getimagesize( $uploadTempFile );

    $srcImage = imagecreatefrompng( $uploadTempFile );    
    imagesavealpha( $targetImage, true );

    $targetImage = imagecreatetruecolor( 128, 128 );
    imagecopyresampled( $targetImage, $srcImage, 
                        0, 0, 
                        0, 0, 
                        128, 128, 
                        $uploadWidth, $uploadHeight );

    imagepng(  $targetImage, &#39;out.png&#39;, 9 );

Can PNG image transparency be preserved when using PHP&#39;s GDlib imagecopyresampled?


I want to load a PNG image encoded in Base64 to canvas element. I have this code:

    &lt;html&gt;
    &lt;head&gt;
    &lt;/head&gt;
    &lt;body&gt;
    &lt;canvas id=&quot;c&quot;&gt;&lt;/canvas&gt;
    &lt;script type=&quot;text/javascript&quot;&gt;
    
    var canvas = document.getElementById(&quot;c&quot;);
    var ctx = canvas.getContext(&quot;2d&quot;);
    
    data =  &quot;data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAUAAAAFCAIAAAACDbGyAAAAAXNSR0IArs4c6QAAAAlwSFlzAAALEwAACxMBAJqcGAAAAAd0SU1FB9oMCRUiMrIBQVkAAAAZdEVYdENvbW1lbnQAQ3JlYXRlZCB3aXRoIEdJTVBXgQ4XAAAADElEQVQI12NgoC4AAABQAAEiE+h1AAAAAElFTkSuQmCC&quot;;
    
    ctx.drawImage(data, 0, 0);
    
    &lt;/script&gt;
    &lt;/body&gt;
    &lt;/html&gt;

In Chrome 8 I get the error: `Uncaught TypeError: Type error`

And in Firefox&#39;s Firebug this: &quot;The type of an object is incompatible with the expected type of the parameter associated to the object&quot; code: &quot;17&quot;

In that base64 is 5x5px black PNG square that I have made in GIMP and turn it to base64 in GNU/Linux&#39;s program base64.

Base64 PNG data to HTML5 canvas

There are different ways to show graphics in a page next to text.
I need to include a graphic/icon that indicates a new tab will be opened.

I know it&#39;s possible to do using at least these different methods:
- Unicode character from default fonts
- Unicode character from CSS loaded fonts
- Inline SVG
- Inline PNG

Please suggest a method to do this, and explain why or why not it&#39;s robust on different browsers and operating systems.




Most robust method for showing Icon next to text

Why am I getting the message &quot;Not a JPEG file: starts with 0x89 0x50&quot; when I try to open my jpg file?


Why am I getting the error: &quot;Not a JPEG file: starts with 0x89 0x50&quot;

I have an app that will display a bunch of images in a slideshow.  Those images will be part of the bundle, thus distributed with the app. 

All the images are photographs or photographic, etc.

I&#39;ve read that it&#39;s preferred to use PNG as the image format, but seeing that the JPG version will be much smaller, I&#39;d rather be using that.

Are there any guidelines which format to use and in which case?

When to use PNG or JPG in iPhone development?

I have a canvas element with a drawing in it, and I want to create a button that when clicked on, it will save the image as a png file. So it should open up the save, open, close dialog box...

I do it using this code

	var canvas = document.getElementById(&quot;myCanvas&quot;);
	window.open(canvas.toDataURL(&quot;image/png&quot;));

But when I test it out in IE9, a new window opens up saying &quot;the web page cannot be displayed&quot;
and the url of it is:

    data:image/png;base64,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




Anyone know how to fix this?

how to save canvas as png image?

I&#39;m trying to convert a PDF to a PNG image (at least the cover of one). I&#39;m successfully extracting the first page of the PDF with pdftk. I&#39;m using imagemagick to do the conversion:

    convert cover.pdf cover.png

This works, but unfortunately the cover.png comes through incorrectly rendered (some of the alpha object in the PDF aren&#39;t rendered properly). I know ImageMagick uses GhostScript to do the conversion and if I do it directly with gs I can get the desired results, but I&#39;d rather use the convert library as it has other tools I&#39;d like to leverage.

This command in GhostScript accomplishes the desired image:

    gs -sDEVICE=pngalpha -sOutputFile=cover.png -r144 cover.pdf

I&#39;m wondering is there any way to pass arguments through convert to GhostScript or am I stuck with calling GhostScript directly?





Converting a PDF to PNG

As a general rule of thumb when is it appropriate to make a gif interlaced, a png interlaced and a jpeg progressive?

Especially when publishing the image on the web.

When to interlace an image?

I&#39;m having problems with a transparent PNG image showing black dithered pixel artifacts around the edge of the non transparent part of the image.  It only does this in Internet Explorer and it only does it from a Javascript file it is used in.

Here&#39;s what I&#39;m talking about...
`http://70.86.157.71/test/test3.htm` (link now dead)
...notice the girl in the bottom right corner. She has artifacts around her in IE8 (I haven&#39;t tested it in previous versions of IE, but I&#39;m assuming it probably does the same). It works perfectly in Firefox and Chrome. The image is loaded from a Javascript file to produce the mouseover effect.

If you load the image all by itself, it works fine.
Here&#39;s the image...
`http://70.86.157.71/test/consultant2.png`

How to fix this?

The image was produced in Photoshop CS3.

I&#39;ve read things about removing the Gama, but that apparently was in previous versions of Photoshop and when I load it in TweakPNG, it doesn&#39;t have Gama.


PNG transparency issue in IE8

I want to convert SVG images to PNG files with transparent background and anti-aliased edges (using semi-transparent pixels). Unfortunately I can&#39;t get ImageMagick to do the anti-aliasing, the edges always look terrible. Here&#39;s what I tried:

    convert +antialias -background transparent  in.svg -resize 25x25 out.png

Any ideas or a different command line tool I could use?

Convert SVG to transparent PNG with antialiasing, using ImageMagick

I have about 200 grayscale PNG images stored within a directory like this.

    1.png
    2.png
    3.png
    ...
    ...
    200.png

I want to import all the PNG images as NumPy arrays.
How can I do this?

Importing PNG files into Numpy?

I have stacked into the question: I need to plot the image with DPI=1200 and specific print size.

By default the png looks ok...
![enter image description here][1]

    png(&quot;test.png&quot;,width=3.25,height=3.25,units=&quot;in&quot;,res=1200)
    par(mar=c(5,5,2,2),xaxs = &quot;i&quot;,yaxs = &quot;i&quot;,cex.axis=1.3,cex.lab=1.4)
    plot(perf,avg=&quot;vertical&quot;,spread.estimate=&quot;stddev&quot;,col=&quot;black&quot;,lty=3, lwd=3)
    dev.off()

But when I apply this code, the image became really terrible it&#39;s not scaling (fit) to the size that is needed. What did I miss? How to &quot;fit&quot; the image to the plot?

 ![enter image description here][2],

 


  [1]: http://i.stack.imgur.com/v51Aj.png
  [2]: http://i.stack.imgur.com/sueTP.png

R plot: size and resolution

I want to know about uses of png files. There are two formats available for *png images*; one is **png8** and the another one is **png24**. 

I would like to know that if I use either type in my `html` page, will there be any error? Or is this only quality matter?

What is difference between png8 and png24

I&#39;ve been a web developer for quite some time, and I am used to transforming all my designs into the png file format in order to build my webpages. Despite the fact that png, contrary to jpg, allows transparency in the images, is it a better solution? 

The question regards page loading time and best webdesign practices, as well as file size versus quality of the images.

What do you think is the best solution to use?

webdesign - jpg or png, which one is the best for web

Is there any free tool available for creating and editing PNG Images?

Free tool to Create/Edit PNG Images?

    convert input.png -extent 100x100 -gravity center -background white output.png

If the input is 50x50 the surrounding background is white. Can I somehow set this to transparent without declaring any color within input as transparent?

ImageMagick extend canvas with transparent background

I&#39;m building an app that uses a lot of images, so it&#39;s getting pretty big. I got more than 15mb in PNG images, and if I convert those images to JPG I would get 5MB or less! So, why should I use PNG instead of JPG?

I know that PNGs are preferred, but what would I lose with JPG?

EDIT: Thank you everybody!

Just a note: Since I got my answer and turns out that I will need to use PNG in most files, I found out that website http://tinypng.org/ , and that&#39;s helping me a lot. My 15mb of images are now 7mb. So, if anyone is in the same situation that I am, I hope that it helps!

Why should I use PNG and not JPG?

I have a bunch of high quality PNG files.  I want to use PHP to convert them to JPG because of it&#39;s smaller file sizes while maintaining quality.  I want to display the JPG files on the web.

Does PHP have functions/libraries to do this?    Is the quality/compression any good?

Use PHP to convert PNG to JPG with compression?

I found JPG does not support transparency, the alpha value is always 255. I am wondering only png supports transparency?

Only PNG supports transparency, is that true?

I am currently working on an application that requires high-performance conversion of an unpadded byte array to either a PNG or JPEG. The image format doesn&#39;t matter, just as long as it&#39;s fast.

I have tried the .NET libraries and the performance is very bad. Can anyone recommend a good freeware library for this?

EDIT: the byte[] is an 8bit grayscale bitmap

Converting a byte array to PNG/JPG

Calling

    image = Image.open(data)
    image.thumbnail((36,36), Image.NEAREST)

will maintain the aspect ratio. But I need to end up displaying the image like this:

    &lt;img src=&quot;/media/image.png&quot; style=&quot;height:36px; width:36px&quot; /&gt;

Can I have a letterbox style with either transparent or white around the image?

PIL: Thumbnail and end up with a square image

So I have seen quite a few ways to darken images with CSS, including ones with rounded corners, but my problem is different.

Let&#39;s say I have an .png image that looks like a little dog (just go with it, I don&#39;t have any good examples), when I place it on my page, I give it dimensions of 100 x 100.

But I can&#39;t just overlay something on it, or tint the entire image, as it will cause the background of the dog to be tinted as well, which looks ugly.

Is it possible to tint an image of arbitrary shape with CSS?

(I&#39;m assuming you understand my point, and useless code is not necessary)

Thanks!

Darkening an image with CSS (In any shape)

When I click on an image link right now, Chrome downloads the image instead of opening it. 

Even if I right-click and select `Open link in new tab` Chrome *still* downloads the image, and I have to go through the extra steps of opening the file for viewing manually.

This feels like a mime-type issue to me, but why would Chrome not recognize &quot;image/png&quot; as a valid mime-type for viewing? All PNG images display just fine in an HTML page.

NOTE: This only happens for PNG images.

Chrome downloads PNG image links. I want them to open for viewing in a new tab. How do I make Chrome do that?

I&#39;m having an issue with attempting to save some plots with transparent ellipsoids on them if I attempt to save them with .ps/.eps extensions. 

Here&#39;s the plot saved as a .png:
![png][1]

If I choose to save it as a .ps/.eps here is what it looks like:
![ps][2]

How I got around this, was to use ImageMagick to convert the original png to a ps. The only problem is that the image in png format is about 90k, and it becomes just under 4M after conversion. This is not good since I have a lot of these images, and it will take too much time to compile my latex document. Does anyone have a solution to this?

  [1]: http://i.stack.imgur.com/w55jg.png
  [2]: http://i.stack.imgur.com/loXbC.png

All Png Solutions on Gang of Coders

Total of 42 Png Solutions