Is it possible to make a pixel transparent using Windows Paint?

Question

I have created an icon with round corners and I want the remaining part behind those round corners to be transparent (Not white) when I use it in windows.

Is it possible to do this just by using Windows 7 paint application? Or is there any simple trick or small application that can do this?

If there is no other way, how can I do this in Gimp?

Answer 1

With Paint, I don't know.

With Gimp,

1. Make a regular icon (square corners)
2. Make sure there is an alpha channel: Layer > Transparency > Add alpha channel (if its grayed it's already there)
3. Check View > Snap to canvas edges
4. Start the "Rectangle select" tool
5. Select the whole image (which is made easier by the snap setting in #3)
6. In the "Rectangle select" options, check Rounded corners, and adjust the roundness radius is the slider that appears below
7. [Enter] to "commit" the selection when happy
8. Select > Invert
9. [Delete] or Edit > Clear. You should now see the transparency checkerboard pattern in the corners.
10. Export to a transparent-capable format such as PNG