WhatsApp not opening while sharing photos from Photos app

So this is a weird one. Adding photos to a chat from within WhatsApp is no problem. However sharing a photo to WhatsApp from within the Photos app does not work for all photos. After pressing share and selecting WhatsApp the screen shrinks a bit, stays like that for a moment and then returns to its normal size. All sharing options remain visible and I can then select WhatsApp again. But other then a small shrinking reaction from the main screen nothing happens, no matter how often I click on WhatsApp. WhatsApp simply does not open.

Sharing that same photo from within WhatsApp by selecting a chat and then + is no problem.

This problem does not occur for all photos. Some can be shared from within WhatsApp without problems.

Possible origin of the problem: the user had chosen not to share all photos with WhatsApp so originally some photos could not be seen by WhatsApp. We corrected this in Settings and restarted the Phone afterwards. But this did not solve the problem. The phone has not been restarted. Photos and WhatsApp have been closed manually several times