I often need to make a transparent image – I figured out that the image type needs to be a .gif file.
My tool of choice – for its simplicity and rich functionality is an old version of Jasc Software’s Paint Shop Pro – yup, it’s old, but it does the trick! The version that I have was from the Jasc Software days, but I see now that it’s been “absorbed” by Corel.
Thanks to http://www.hypergurl.com/transparentgif.html for much of the info below:
Here is a simple technique to make transparent gifs with Paint Shop Pro:
Open an image and click on the ‘Dropper Tool’ and right click on the image’s background. This will set the colour palette to match the background colour of your image.
Click on Colours->Set Palette Transparency, then check the option “Set the transparency value to the current background colour”, then click OK, and then save the image as a .gif file.