Helpful Suggestions

• Suppose that the picture that you wanted to make transparent didn't have a uniform background color. In otherwords, the area that you want to make transparent is cluttered up with a lot of stuff drawn in different colors. This can easily be the case for pictures that have been scanned in. I guess you could make each and every one of the colors in the background transparent, but what happens if the actual image that you want to see contains the same colors as the background?
• Make a backup copy of your picture because what I'm about to explain is not a robust error proof technique. I've had xpaint (the program I'm about to explain) severly chew up and vomit some of my pictures.
• To get around this problem of many colors in the background of our picture, we can use a picture editor such as xpaint. To get this running, type setup xpaint (if you've never set it up before) and then type xpaint &. I haven't been able to get this to run on the SUNs, but it works on the IBMs. I haven't tried it on the SGI machines yet - so this is another experiment. Xpaint is simple and very intuitive to use. You can use the brush to paint over the background pixels to make then all one color (make sure that the color you choose is not in the actualy image that you want to display). You can pull down fat bits from the image menu once you've loaded up a picture to do tedious pixel editing.
• Once you've edited the picture, look at it again with Xv and note the RGB color of the pixels that you want to make transparent and then just run giftool on it again.
• This may sound like a tedious way of doing things, but this is what I do. I have done this process many times to get the images on my home page look decent.
• These techniques work fine if the picture format is a GIF. But if it is not a GIF, then you have to convert it to a different file format. Xv does this for you. If you load up a GIF or any picture using Xv and then save it, you will be given many options of file types that you can save to. So, if you have a JPG (sometimes JPEG) that you want to work with, load it up in Xv then save it as a GIF file.