Convert an image (selected by path) to base64 string

How do you convert an image from a path on the user's computer to a base64 string in C#?

For example, I have the path to the image (in the format C:/image/1.gif) and would like to have a data URI like data:image/gif;base64,/9j/4AAQSkZJRgABAgEAYABgAAD.. representing the 1.gif image returned.

Try this

using (Image image = Image.FromFile(Path))
{
    using (MemoryStream m = new MemoryStream())
    {
        image.Save(m, image.RawFormat);
        byte[] imageBytes = m.ToArray();

        // Convert byte[] to Base64 String
        string base64String = Convert.ToBase64String(imageBytes);
        return base64String;
    }
}

Get the byte array (byte[]) representation of the image, then use Convert.ToBase64String(), st. like this:

byte[] imageArray = System.IO.File.ReadAllBytes(@"image file path");
string base64ImageRepresentation = Convert.ToBase64String(imageArray);

To convert a base64 image back to a System.Drawing.Image:

var img = Image.FromStream(new MemoryStream(Convert.FromBase64String(base64String)));

Since most of us like oneliners:

Convert.ToBase64String(File.ReadAllBytes(imageFilepath));

If you need it as Base64 byte array:

Encoding.ASCII.GetBytes(Convert.ToBase64String(File.ReadAllBytes(imageFilepath)));

This is the class I wrote for this purpose:

public class Base64Image
{
    public static Base64Image Parse(string base64Content)
    {
        if (string.IsNullOrEmpty(base64Content))
        {
            throw new ArgumentNullException(nameof(base64Content));
        }

        int indexOfSemiColon = base64Content.IndexOf(";", StringComparison.OrdinalIgnoreCase);

        string dataLabel = base64Content.Substring(0, indexOfSemiColon);

        string contentType = dataLabel.Split(':').Last();

        var startIndex = base64Content.IndexOf("base64,", StringComparison.OrdinalIgnoreCase) + 7;

        var fileContents = base64Content.Substring(startIndex);

        var bytes = Convert.FromBase64String(fileContents);

        return new Base64Image
        {
            ContentType = contentType,
            FileContents = bytes
        };
    }

    public string ContentType { get; set; }

    public byte[] FileContents { get; set; }

    public override string ToString()
    {
        return $"data:{ContentType};base64,{Convert.ToBase64String(FileContents)}";
    }
}

var base64Img = new Base64Image { 
  FileContents = File.ReadAllBytes("Path to image"), 
  ContentType="image/png" 
};

string base64EncodedImg = base64Img.ToString();

You can easily pass the path of the image to retrieve the base64 string

public static string ImageToBase64(string _imagePath)
    {
        string _base64String = null;
    
        using (System.Drawing.Image _image = System.Drawing.Image.FromFile(_imagePath))
        {
            using (MemoryStream _mStream = new MemoryStream())
            {
                _image.Save(_mStream, _image.RawFormat);
                byte[] _imageBytes = _mStream.ToArray();
                _base64String = Convert.ToBase64String(_imageBytes);
    
                return "data:image/jpg;base64," + _base64String;
            }
        }
    }

Hope this will help.

You can use Server.Map path to give relative path and then you can either create image using base64 conversion or you can just add base64 string to image src.

byte[] imageArray = System.IO.File.ReadAllBytes(Server.MapPath("~/Images/Upload_Image.png"));
        
string base64ImageRepresentation = Convert.ToBase64String(imageArray);

That way it's simpler, where you pass the image and then pass the format.

private static string ImageToBase64(Image image)
{
    var imageStream = new MemoryStream();
    try
    {           
        image.Save(imageStream, System.Drawing.Imaging.ImageFormat.Bmp);
        imageStream.Position = 0;
        var imageBytes = imageStream.ToArray();
        var ImageBase64 = Convert.ToBase64String(imageBytes);
        return ImageBase64;
    }
    catch (Exception ex)
    {
        return "Error converting image to base64!";
    }
    finally
    {
      imageStream.Dispose;
    }
}

Based on top voted answer, updated for C# 8. Following can be used out of the box. Added explicit System.Drawing before Image as one might be using that class from other namespace defaultly.

public static string ImagePathToBase64(string path)
{
    using System.Drawing.Image image = System.Drawing.Image.FromFile(path);
    using MemoryStream m = new MemoryStream();
    image.Save(m, image.RawFormat);
    byte[] imageBytes = m.ToArray();
    tring base64String = Convert.ToBase64String(imageBytes);
    return base64String;
}

The following piece of code works for me:

string image_path="physical path of your image";
byte[] byes_array = System.IO.File.ReadAllBytes(Server.MapPath(image_path));
string base64String = Convert.ToBase64String(byes_array);

The reverse of this for the googlers arriving here (there is no SO quesion/answer to that)

public static byte[] BytesFromBase64ImageString(string imageData)
{
	var trunc = imageData.Split(',')[1];
	var padded = trunc.PadRight(trunc.Length + (4 - trunc.Length % 4) % 4, '=');
	return Convert.FromBase64String(padded);
}

Something like that

 Function imgTo64(ByVal thePath As String) As String
    Dim img As System.Drawing.Image = System.Drawing.Image.FromFile(thePath)
    Dim m As IO.MemoryStream = New IO.MemoryStream()

    img.Save(m, img.RawFormat)
    Dim imageBytes As Byte() = m.ToArray
    img.Dispose()

    Dim str64 = Convert.ToBase64String(imageBytes)
    Return str64
End Function