Ok, so I'm trying to get my submission ready for the Threadless Loves Lomography competition but I can't get my thumbnail image down to a 10kb size. I can get it down to 12kb but not 10. Any suggestions?

Uh...anyone know how to make a thumbnail 4kb without altering the 100 x 70 requirement and without using a file name other than gif. I can't get it. My file I'm trying to submit is 68kb for some reason. I've tried everything. oh and I'm using photoshop. Help please