I also ask that you don't link directly to the images themselves. While I have no particular objection to pornography, some of my viewers might. For those people, I prefer to keep this site free of such links. I also prefer to avoid linking to site's that use pop-ups. If you are using a free host that requires you to use their advertising pop-ups, that is acceptable.
Few things are more annoying than pop-up advertising.
Pop-ups that automatically appear when a visitor leaves your site will disqualify your site from appearing on my links page. Your site's main page should make it easy to see what kind of site it is, and provide an easy way for visitors to get to your content. If it takes me more than a few seconds to locate your site's content, I will not link to you.