Hints for showfoto in main

Warnings

• metainfo-validation-issue
  Validation of the metainfo file found a problem: The component is missing a summary (<summary/> tag).
• screenshot-save-error
  Unable to store screenshot for 'https://userbase.kde.org/images.userbase/thumb/5/5d/PhotoTut1_2.png/550px-PhotoTut1_2.png': Can not store source screenshot: Failed to load image data: Unrecognized image file format