Suggested tag: avats, or alternative_version_at_the_source.

There is already tag for bigger_version_at_the_source, but sometimes there is a picture that you upload which has few similar versions (for example post #403478 and its children) but you don't have time/want to upload it. This tag will be useful for people who want to improve their upload limit without much effort.

Sounds a good idea for a tag to me. I always upload posts that have alternate versions that I really don't want to upload every single version.

Support.

ULing works from Pixiv takes ages because of all the open-in-new-window business they have set up in their UI and sometimes I only like 1 of the images in a 'manga' stack (which is basically like a photoset only clunkier).

Maybe if folks are really in love with a character in something I upload they will want to see more of them in doodles I don't personally find worthwhile to put up.

Sure, sounds good

I've created alternative_version_available tag. Comparing to bvats I think that it is wise to allow listing alternative versions also in description and comments. Not all pics have one url for all versions and source should direct to original picture.