[PIETER]

Here is a few that I'veFound:

http://www.pbase.com
http://www.deviantart.com
http://www.desktopheap.com
http://www3.photosig.com/
http://www.imahosting.com/uploadsig.php
http://100grams.com


I don't know weither they are direct linking for free space.

Add some you know.