I keep what I save from e621 in one massive folder now, and simply append all the tags on the submissions to the downloaded images (converting to .jpg where necessary - .pngs cannot store tags in metadata...). This saves me from mountains upon mountains of folders for sorting and the dilemma of where to put one file if it fits in multiple folders. One folder, with everything in it tagged, is easier to search on the fly.
However, downloading, converting, and tagging any file takes a while - so much so that I basically only download/convert/tag in bulk every six months or so, when I can be bothered to sit down and spend a few hours clearing my download backlog.
I'm hoping there's a tool out there that can save me a lot of trouble with this, but all my searches for 'e621 downloader and tagger' return results for programs that take a tag input and download everything they can find with that tag, which is approaching my issue from the wrong direction.
Ideally, I'm looking for an extension that adds a button to the toolbar or right-click image menu that downloads the image, converts it to .jpg if necessary, and grabs all the tags on the submission and sticks them in the file's metadata. Does such a thing exist?
Updated by savageorange