[Zope] FileSystemSite does not register file extension

Hi all. I'm using the FileSystemSite product in a pure Zope application. Inside it, I'm registering some extensions (gif, png, jpg, etc.) in order to work with a subclass of FSImage. The problem now is that the registration works for all extensions but the gif one. This has changed from one day to another. Now, I understand this is something we did, but I've no clue in what we could have changed. Works = With a png, I've my FSImage subclass used. With a gif, I've the FSImage used. Also, with the gif I've the '.gif' added to the id of the object, while with the other image I don't have it. Any suggestion? -- Icube Srl http://www.icube.it/