YorkieTalk does not allow picture uploading from other sites for security reasons. You can upload pictures from your own computer only. We do not allow pictures in signatures either.
Here is the link on how to post pictures:
http://www.yorkietalk.com/forums/showthread.php?t=1994
Or, you can also just put in the link to your photos in your posts if you can not get that to work. Thank you.