Watermark per image ( invidual watermark)

[pgrzegorc]

I 've read a few hacks how to make watermak for the iimage,
but I can't see and understand:
how to make watermak per image ( invidual watermark) means that I would like under uploading to insert individual watermark to the picture as well - that's nothing important about performance uplaoding.
Because I have a few kind of albums and a lot of people whos have access to upload pictures, and of cource anyone should have a own individual watermark which I would like to choose under uploading??? I would like to have about 20 watermark ( I have 20 people with access to upload).

How to do this
Everything will be hopefull, notices, sources, link as well


Regards,
Pawel