Editing Incubator escapee wiki:Help desk/Archive 7 (section)

==Possible bug in uploading an image?==
I wrote an article about Bill Tilden the tennis player, then found an old public-domain photo of him.  It was stored on my computer as C:\Aspects II\Bill Tilden.jpg.  A couple of days ago I uploaded it and put it into the article with no problems.  Today I went back to the original picture on my computer and cropped it slightly.  I then saved it under the same name in the same location.  Then I came back to Wikipedia and uploaded the new image through the usual process.  I got a Warning saying that the name had been changed to Bill_Tilden.jpg (as it did the first time) and a second warning saying that this new file would overwrite the existing file of the same name.  So I uploaded the new file.  To my surprise, however, it did ''not'' replace the existing one.  I exited Wikipedia completely, then tried the same process 2 more times.  Each time I was told that my new file had replaced the old one.  But the same picture kept appearing in the article.  And when I went to the Image page, where it shows a picture of my image, it was always still the original picture, even though the History said I had replaced it three times.

Finally I went back to my C:\Aspects II folder, renamed the picture Bill_Tilden_Hitting_a_Backhand.jpg, and moved it to C:\Aspects.  I then returned to Wikipedia and imported it again under the new name.  I then went to the article and changed the name of the image to be shown to the new name.  Et voila, the cropped image showed up in the article.

Was I doing something wrong here, or is there some bug that prevents one image from overwriting another?  Or is this some sort of security device that the editor isn't told about when he's trying to change the picture?  [[User:Hayford Peirce|Hayford Peirce]] 20:13, 18 Aug 2004 (UTC)
:Sounds to me like it might be a caching issue: the picture updated but you were looking at an old version.  [[User:Isomorphic|Isomorphic]] 21:37, 18 Aug 2004 (UTC)

::This is the MediaWiki picture caching bug. I submitted this at the SourceForge bug tracker but I can't find it at [http://bugzilla.wikipedia.org/ bugzilla.wikipedia.org], so I'll give an explanation here and maybe someone will submit it again in the proper place.

::Consider the image on [[Wikipedia:Village pump]]; its URL is http://en.wikipedia.org/upload/thumb/b/ba/100px-Village_pump_clear.png.  Here's what I get if I request the image (my typing in bold):

  $ '''telnet en.wikipedia.org 80'''
  Trying 207.142.131.235...
  Connected to en.wikipedia.org.
  Escape character is '^]'.
  '''GET /upload/thumb/b/ba/100px-Village_pump_clear.png HTTP/1.1'''
  '''Host: en.wikipedia.org'''

  HTTP/1.0 200 OK
  Server: Apache/1.3.29 (Unix) PHP/4.3.4
  Cache-Control: max-age=2592000
  Expires: Tue, 14 Sep 2004 18:01:38 GMT
  Last-Modified: Tue, 06 Jul 2004 05:34:34 GMT
  ...

::Note the Expires header. This is telling my browser and all proxy caches between me and Wikipedia that they need not request the image again until 14 Sep 2004. So if someone changes that image today I won't see it for another month or so (unless it drops out of all the caches). Note that it does me no good to flush my browser's cache if the image remains in my ISP's proxy cache.

::The solution is to incorporate the revision number into the URL for the image, for example http://en.wikipedia.org/upload/thumb/b/ba/'''r1'''-100px-Village_pump_clear.png. Then when someone changes the image my browser will fetch '''r2'''-100px-Village_pump_clear.png and I will see the change immediately. This imposes a cost on the server, as whenever anyone updates an image the server will have to flag all articles using that image as out of date, but I think that as image updates are rare this will be a supportable cost. [[User:Gdr|Gdr]] 11:18, 2004 Aug 19 (UTC)