I've checked in a quick tweak in r79029 that adds thumbnail previews of
image files on Special:Upload before you submit the form, in browsers
supporting the HTML 5 FileAPI [1] (such as the current stable releases of
Firefox and Chrome).
This helps with a longstanding problem that's bugged me for years: when the
AJAX filename conflict thingy trips, you get a thumb of the *existing* file
but not of the file you're about to upload, making comparisons harder! Now
you've got the file you just selected sitting right above it, which is
rather more convenient.
Files larger than 10MB aren't previewed as a guard against accidentally
hitting a really big file that eats your browser's memory and kills
everything. :)
On browsers that don't include the FileAPI FileReader class, or when
selecting a file that isn't a PNG, JPEG, GIF, or SVG file, you won't see any
change in behavior.
[1]
http://www.w3.org/TR/FileAPI/
[2]
https://developer.mozilla.org/en/using_files_from_web_applications
-- brion vibber (brion @
pobox.com)