Gwenview and pictures in Portait Mode

Gwenview always shows pictures in landscape mode, all other programms are able to show these pictures in a correct orientation. Only Gwenview fails.
Why? And what is to do for using Gwenview in a usefull way?

Not sure what you mean. Some portrait in Gwenview and Qimgv. Looks portrait to me.

Pictures taken by the Smartphone are shown in the correct way, CR2 and CR3 taken with Canon EOS 5DsR and R5, all ok. JPG out of the Canons, imported with Digikam, are all shown in landscape.

This sounds like its using exif lossless rotate on the jpeg. Check digicams export settings.