img src wrong when percent escapes are in uploaded filename (easy to fix)

Upload filename:
some%20file.jpg

Filename on server:
/var/www/(...)/files/some%20file.jpg

src:
/files/some%20file.jpg

Request translated by webserver daemon:
/var/www/(...)/files/some file.jpg
-- does not exist

This bug affects uploads where the filename contains percent escapes and characters like # and ? that are interpreted by webserver applications (# and ?: UNIX clients might upload files containing these characters).
I haven't verified the # and ? problem.

Supposed fixes, either:
- Remove percent escapes from upload filename
- Escape percent signs in img tag output (ugly or not backward compatible)

I think the first fix would be best and should be easy to implement.