Use imgur for linking to images. Linking to tumblrs and ad-heavy sites is not allowed. No morphs or otherwise heavily photoshopped images. Use Google images to identify the name or source of models posted. Search, post your results, and reap that sweet karma.
Please send a email to tumbex. Obviously, they decided that my site was no longer acceptable and they set up specific rules so that tumbex users no longer have access to the contents of tumblr. It's unfortunate, I loved tumblr, that's why I created tumbex. Using tumblr with an easy, clean and efficient interface was my goal.