Create a Small Image File?

Ok, I have Adobe Photoshop CS2, and I was wondering how I could make a file that was small. Let's say for an avatar, I'm trying to make a 100x100 smaller than 19.5kb, except it won't go below 26kb. How would I do this? I've never had the need to make a small image file, so this is kinda bothering me.

Off topic, I just discovered that nVidia had the Quadro series (lol). Would these help with photo editing? My friend does a lot of that, so he might get one.

What format are you saving the file as?

By changing the format of the picture, it lowers, or increases the size of the image.

Saving the picture as a .gif usually lowers the image size by enough to be able to use it.

sweet, it worked, as you can see