As long as the gallery link and or image (i.e. thumbnail) is only skimming to others tgp/mgp's and not to redirect or other sponsors then
www.pussymoney.com allows it.
I understand many tgp/mgp sites get the majority of traffic from such trades and I would rather you have fresh new traffic clicking through 50% of the time and grow with you. Of course not all tgp/mgp sites skim.
Now skimming on paid slots is entirely another story and would piss me the hell off.