What each user has downloaded ... and creditssystem

Hello and sorry for my poor english.

1. What each user has downloaded:

I need a chance to see a list of all downloads.
example:
Time | PictureName | PictureID | User | Credits left
10:34p.m. 23.11.2008 | Tower.jpg | John Doo | 10
10:33p.m. 23.11.2008 | Cityblue.jpg | Frankenstein | 0
.....

2. Creditssystem

The next idea for my Gallery is a creditpointsystem, so
only people with creditpoints can download pictures.
All other can only show the Thumbnails and a Watermark_version of the Picture.

I didnt found something like that and now my question to you: is that possible and
have anybody time to help me?

greetz
Max