Linkshare sounds like a clever candy wrapper around getting people to have large, prominent banners that link back to rendo - something that you are typically paid for everywhere else.

The Linkshare "qualification rules"

*Qualifying sites are those that are related to digital art.
We will not approve any sites that are money making schemes, click brokering, exclusively link exchanges, sites that are under construction, pornographic sites or any sites with a primary focus on images of rape, torture, sexual acts, or physical arousal. When you submit your link, it will go into pending until the legitimacy of the site and compliance with the Upload Agreement can be verified. Once the site is approved, and the LinkShare code confirmed as active on your site, the Renderosity Gift Certificate will be awarded and you will be notified. 

"Physical arousal" is very worrisomely vague, as is "sexual acts" and "pornographic".  I'm guessing "You know what we mean!" is the prepared response to any complaint about that.

Considering all you get is a) traffic that you may or may not ever see or even want, and b) a one-time (limited time only!) $5 coupon, Rendo makes out like bandits on it.  But hey, there's no purchase necessary!

And the linkshare program appears to automatically draw from the gallery, which is fairly likely the real reason for the thumbnail rules change, seems to me.

My Freebies