C# Resized images have black borders

Question

I have a problem with image scaling in .NET. I use the standard Graphics type to resize images like in this example:

public static Image Scale(Image sourceIm         


        

Answer 1

The problem lies in the fact that your bitmap toReturn has a black background by default. Copying a new image over it makes black or gray borders.

The solution is to remove the black default background, by calling:

toReturn.MakeTransparent();

Since after this line you'll be drawing on a new image without any background color the borders will disappear.