If the image quality is quite good to begin with you can use 40% on thumbs and 60% on 640 length images and they still look quite good since there is no source image to compare it to.
The more amateur style content seems to degrade more, but it's not *so* bad.
I don't think someone will buy a membership to a site based on your free site or gallery images unless they are sponsor images.
The ad copy must be really well thought out...and links positioned well.
I was crusing GG's LOR site.
In viewing a bunch of free sites that positioned their 'Enter /Exit' links in the same areas where their Gallery 1/ Gallery 2 link will appear on the next pages it became clear it would be very easy to surf those sites.= and bypass the sponsor ads.
Then I came across a few that had the Enter / Exit links well below the rest of the content and that made me scan the page and look at the ads. That was smart.
Then when I clicked on the Enter link I automatically scrolled down to where I
thought the Gallery links would be after being "trained" by all the other sites.
They had Sponsor links there.
The Gallery links were at the very Top.
I had to search the page a *bit* by scrolling up/down. Not that annoying since you know it's there, but the layout has to get more click throughs than the rest of the sites that put the Enter/Exit and gallery links in the same positions.
I never forget what MML stated on a radio show "You don't
want them to get to your content."
When you start to think you get 1 stinkin' free site per day and what on partner accounts (2?) you
really need to maximize each on of those free sites for max clickthrough.
Regardless of whether the pics you have a great, once they get to the sponsors page it's up to their tour and site to do the final sale.
Just my humble newbie .02 worth.