This is the firstscript from the set of two that implement automatic filename and save path formatting for images being saved from tumblr based on image post tags. Best used with the second script in tandem. Both require Flash.
This script stores image tags for posts that you see on tumblr so that this information can be used later when you open images on a new tab. Additionally it marks images already saved with the userscript and makes some slight changes to tumblr design. The changes include linking images from posts directly to the image file itself bypassing the /image/ page, linkifying even small images that don't have HD version in single image posts and linkifying inline images in non-photo posts. The latter links images either to their HD version (for newer posts that have them), or to Google reverse image search so you can try to find HD yourself.
Usually the script does not require user interaction unless it hits flash cookie size limit, then it'll prompt the user to increase it.