I have a friend who's running an image hosting site (this is why I was looking for scripts a month ago)
In his first week, he blew about $200 on PPC to get traffic for it, made about $15 back in affiliate sales, and the traffic kind of died after the PPC campaign did (and we found a single word keyword that gets plenty of looksie, but almost no competition: go figure?).
We're now working on the whole SEO bit, and trying to get the thing to just go viral on its own.
In my experience, I'd say you've got a couple of ways to go about it with an image gallery.
First thing is stop buying traffic after a couple of weeks and hope it gets sticky on its own. Also make sure you've got an RSS option for the latest uploads, as people want to see new content.
In terms of making money from it, make sure you're not saturating the ads. People didn't come to see ads, they came to see pics of something.
One add between the menu bar and the pics, and maybe another on the side or the bottom. No fucking Adsense!
If you can figure a way to insert the ads into the image gallery from time to time, all the better. i.e. You've got a gallery of motorbikes, put up a random sprinlking of pics that are actually linked to one of your affiliates. Alternatively, have the ads just look like another row of pics at the bottom.
Finally, in so far as the clicks go, it could be a tracking issue.
Get a tracking script like 202, or even a click-heat-map. If it's showing a few clicks here and there on your ads, talk to your manager and find out what you/they're doing wrong with the tracking.