A number of users with some form of adblocking software installed have reported
that they are unable to view images such as
http://upload.wikimedia.org/wikipedia/en/a/ad/OL0026.jpg whose URL contains the
string "/ad/". As these directories are chosen by random hashing, the end
result is that such users are unable to view a seemingly random set of about
0.1% of our images.
While this is certainly not our fault, such occurrences are common enough (and
confusing enough to the users experiencing them) that a workaround at our end
would be desirable. A simple solution would be to change the image hashing
system to remove the redundant first letter from the subdirectory name, so that
the URL would contain "/x/y/" instead of the current "/x/xy/".