Author: plugwash

Description:
when uploading a new version of an image the old image has a tendancy to remain
there seem to be two seperate problems behind this.

1: scaled images are not regenerated until a page is re-rendered
2: images stay in cache (squid i presume but i could be mistaken) until forced
out of it (using ctrl+refresh).

so to replace a scaled image on a page currently the following sequence is needed
1: upload the new image
2: purge the page w/index.php?title=whatever&action=purge to force the new
scaled image to be generated
3: ctrl+refresh to force the old thumbnail out of cache.

so when an image is updated all pages using it need to be invalidated (same as
when editing a template) and the image needs to be purged from cache.
Furthermore when regenerating a scaled image the old scaled image needs to be
purged from cache.

i figured out this sequence based on trial and error and educated guesses but
most newbies aren't going to have a clue if and when they run into this issue.

shared uploads (commons) further complicate this issue

Version: 1.5.x
Severity: major