renderosity requires the thumbnail to be min of 100 X 100 with 15KB file size max.  In Photoshop CS, I go to "image" then "image size" and nothing I change can get the image to be a min of 15 kb with the pixil size of 100 X 100 min.

I have tried the "save as"  command under "file menu" and even pushing the quality slider to low, the file size does not get to to 15 kb.  Since everybody else seems to be able to do this, I've got to be doing something wrong.  

The original image is 450 X 338 with a file size of 466 kb in TIFF format.  I tried it as a JPEG image also and that did not work either.

What am I doing wrong?