Sometimes when working with an image you want to make a certain
color transparent. When working with a gif file this would make a
round circle look round on any color background. This is actually
very simple once you do it once. Finding the information for this
took me a while so I thought I would pass it on to anyone that was
1. Open your image in the gimp.
2. Right click the image and go to LAYERS then ADD ALPHA
CHANNEL. You won't notice anything happening, but don't be
concerned. It basically adds a transparent layer at the bottom of
your image so when we erase the colors.....it's shows the
transparent layer. Which of course would show whatever was under it
on the screen.
3. Right click on the image again and go to SELECT and then down
to BY COLOR. A window that is all black opens up. Don't change any
of the settings....just use the defaults for now.
4. Now click on the color in the image you want to be
transparent. These colors will now show up outlined.
5. Right click on the image again and go to EDIT and then down
to CLEAR. This should now erase the outlined color you just picked
from the image and the "transparent gimp checkerbox" should show
through. This is the Gimps way of showing you that section is now
6. Right click on the image and choose SAVE AS and make sure to
save as a GIF file if you want the transparency to work on the
Most of this information was gleaned from this webpage: (link dead, sorry)
and of course my Gimp Bible and my Essential Gimp books.
Another fun feature that can be used while using the SELECT and
BY COLOR ..... instead of hitting CLEAR you can FILL W BG COLOR or
the other one FILL W FG COLOR ........... this allows you to change
the colors over the entire image instantly for the particular pixel
color you choose to start with. Very fast and fun once you figure