TIF attached to dispute case isn't displayed

Hi,

TIFs that are attached to a dispute case can't be displayed. PDF files works fine.

The problem already exist directly after the upload.

It doesn't seem to be an authorisation problem (Trace made, RC=0 for each check).

The TIF is uploaded correctly as it can be downloaded and displayed then by windows tools.

Are there any settings needed?

Thanks for any idea in advance

Katja