Since you mention SEO, is this just about site-internal exposure, so exposure to users that are already on the site, or external exposure on other search engines like Google's?
If it's about site-internal exposure, I actually wrote a
blog post back in January that covers a few tips for uploaders that also covers some SEO on Imagefap. The big takeaways from that are basically:
- Uploading new images to old galleries is normally a bad idea, as it's not going to push those galleries up in the search results and your followers are not going to be informed about it and even in the case that you inform them per status update, a lot of them are not going to do the 3+ clicks required to get to the new images.
- Since ImageFap's search engine does not look at the tags & categories when searching for search terms, it's a good idea to also try to weave the most important ones into the title or description.
- To still actually give your galleries tags, as some people are still going to use them. Though you should usually keep them as individual/separated as possible, so e.g. "mature" & "wife" instead of just "mature wife", though if haven't reached the limit of 10 tags then "mature wife" can also be good one to add.
As for external SEO, I only now the basics of the technical site of SEO, but I don't think there is much a user can do on-site other than choose an appropriate title. The tags are used for the metadata keywords, but those have been obsolete for Google's SEO for quite a while afaik and the metadata description is an auto generated one by IF, which is also a bit broken as it has the placeholder text "%listoftags%" in it's text that is probably supposed to be replaced by the actual tags or categories of the gallery.
When it comes to general site SEO there would also be the fact that for gallery results the <title> html tag's text is currently so long and in cases also irrelevant, that Google actually prefers to use the large, bold “Free porn pictures”/”Free [Category] porn pictures” text on top of the gallery results instead for its own search result title, though sadly this and the %listoftags% issue can't be changed without touching the codebase.