1. In Photoshop, select File/ New. Create a file that is 128 pixels by 128 pixels. This will ensure, using the Render/Clouds filter, that your background tile will be seamless. Make sure that your file is in RGB mode, since most filters will only operate on files that are in RGB or grayscale. Set your background color to a magenta, and the foreground color to a pale yellow as shown in the example.

2. Next, select Filters/Render/Clouds. If you don't like the first clouds texture, use Ctrl+F (Command+F on the Mac) to apply the filter again. Continue until you find a texture that you like.

3. In Phototshop 3, select Mode/Indexed, in Phototshop 4, select Image/Mode/Indexedand save this as a gif file. Be sure to experiment with different colors. Try pale aqua and dark violet, or black and white...experiment!

Below are three other cloud backgrounds. The first one was created with turquoise and black selected as the foreground and background colors. The second example was created by adding the Diffuse filter, and the last example was created by using the Noise filter.