I don't think they have any policy against posting images with links in them...do you just mean that you will post a page from the comic and have the link to your website or patreon written somewhere in the image? Because a lot of people do that, I don't think that's a problem, I do that on all my pages.
Regarding adult material, this is from the Content Guidelines:
So, nudity and non-graphic sex is okay as long as you put it behind the NSFW filter, and you only use the NSFW filter on the episodes where there is content of that sort, not the whole comic (although if there's a lot of it, it might be a good idea to mention that in the description), and you don't need to censor things in the episode as long as you use the NSFW filter. Pornography isn't allowed either way, as I understand it. If you're very much in doubt whether or not your material is too pornographic, I'm sure you can email the Tapastic staff and send some of the pages you're in doubt about and ask them, they are very helpful and understanding. You find the rest of the guidelines here: http://tapastic.com/policies/content
Hope this helps 
