Returning an image from a General Handler in .NET

You know how to return a string, you know how to return an integer and you know how to return JSON, but do you know how to return an image from a General Handler file (ashx) in .NET 4.6?

Well if not then fear not as I have the answer.

Simply put you make sure the return type is or an image:

C#

context.Response.ContentType = "image/"  + System.Drawing.Imaging.ImageFormat.Jpeg;

VB

context.Response.ContentType = "image/" + System.Drawing.Imaging.ImageFormat.Png;

We then use the ‘Image’ class from the ‘System.Drawing’ namespace, which can be used in both VB and C#. With this item we can use the method ‘Save’ to instead of saving it to a file, we save it to the http requests ‘OutputStream’ as this is what will be returned to the user.

C#

Using System.Drawing;

## Get your image into the Image class via your own method
Image MyImage = GetImage();

## Save the Image to the OutputStream back to the request
MyImage.Save(context.Response.OutputStream, System.Drawing.Imaging.ImageFormat.Jpeg);

##Clean up after yourself
MyImage.Dispose();

VB

Import System.Drawing

' Get your image into the Image class via your own method
Dim MyImage As Image = GetImage()

' Save the Image to the OutputStream back to the request
MyImage.Save(context.Response.OutputStream, Imaging.ImageFormat.Jpeg)

' Clean up after yourself
MyImage.Dispose()

Here are some helpful links for some further reading:

• HttpContext Class –
  https://msdn.microsoft.com/en-us/library/system.web.httpcontext(v=vs.110).aspx
• System.Drawing Namespace –
  https://msdn.microsoft.com/en-us/library/system.drawing(v=vs.110).aspx
• ImageFormat Class –
  https://msdn.microsoft.com/en-us/library/system.drawing.imaging.imageformat(v=vs.110).aspx
• Image Class –
  https://msdn.microsoft.com/en-us/library/system.drawing.image(v=vs.110).aspx