The large thumbnails use on average 33K apiece.
The small ones use about 6K apiece.
The site has typically around 300 people on the site at once browsing the skin library.
If each user is browsing a library with teh default 10 skins displaying per page, that's 330K just in thumbnails PER user.
Changing the thumbnails saved a full megabit of bandwidth.
We're working on a more sophisticated way of dishing out bandwidth.
We always have two options:
1) Make the site slow for everyone
or
2) Make the site fast for some and not so great for others.
We prefer item 2 with that based on people who create accounts and eventually people who have supported the site through activity on the site (posting, making skins, buying a CD, skin pack, T-shirt, registered user of WB/ODNT/IP/OB/CONV/DX, etc.).
But it'll take awhile for us to fully implement item 2. For now, I think we're going to simply have anonymous users have the small thumbnails and those who have created accounts be able to choose.