Thumbnail not automatically re-rendered when visible image has been replaced
See https://chat.inkscape.org/channel/inkscape_user?msg=J7pBcuMJM5BeqRcJe
User updated their SVG upload and the visible image along with it. However, the thumbnail did not update along with it, and the gallery showed a wrong rendering. Clearing the thumbnail as admin helped as a temp workaround.
The thumbnail should automatically be updated when a user changes the rendering image and / or the SVG.