MediaWiki:Fileexists
From YPPedia
A file with this name exists already, please check $1 if you are not sure if you want to change it. Note: You only need to reupload the image once. If you do not immediately see the new image in the article after uploading the newer version, your web browser is caching the image. In order to refresh your web browser's cache of the image manually, go to the image page (i.e. Image:Example.jpg) and there should be text with a link under the image (Example.jpg (17KB, MIME type: image/jpeg)). Click on that link to view just the image and then use your web browser's reload or refresh button.
