My thoughts are that an RSS feed now is an essential part of the tools that should be available to your affiliates.

An option of 1 to 4 pics and an embed clip option and also a decent amount of descriptive text at least..

There is many that excel at providing this, and there is also many that fall well short, mainly in the descriptive text department... If used right it is good for building SE traffic, An affiliate today has to be a webmaster, programmer, SEO pro and a fucking writer in most cases, Leaving zero time for anything else...

Personally if your galleries do not have descriptive text or your RSS feeds suck in that department then most do not have the time to amend, correct and optimize and simply put it on full auto pilot or don't use the feeds full stop.

Look after your affiliates and they will look after you !.. make their work easier and they will be more ready and willing to promote you to the the hilt, as less time will be spent trying to make shitty affiliate tools work rather than just getting down to the promoting itself...