how about this...
having read your post a couple of times, i think i see what you are after
if so, i think you would be best served by 3 tables...
tblvote needs to have
voteid as pk
imageid (foreign key to imageid in tblimage)
userid (foreign key to userid in tbluser)
tblimage should have all image info required
tbluser should have all user info required
your voting page would show all images from tblimage.
when the image is chosen, update tblvote with imageid selected and userid currently viewing