SUMMARY
When placing a custom stamp (a handwritten signature for example) I'm unable to ensure that it appears correctly and un-pixelated as I'm unable to resize it and fix the aspect ratio that it started with.  

STEPS TO REPRODUCE
1.  create a custom stamp by using configure okular - > annotations and adding in a .png file with handwriting in it (and a transparent background while you're at it).  
2. note that when first placed it is TINY and unintelligible, 
3. now try resizing it (switch to the Browse tool and grab a corner handle on the stamp).  Note the result, it isn't pretty.  

OBSERVED RESULT
the stamp with the handwriting looks like a badly pixelated drawing in the document

EXPECTED RESULT
a reasonable reproduction of a handwritten signature.  

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Majaro 25.1
KDE Plasma Version: 6.5.4
KDE Frameworks Version: 
Qt Version: 6.10.1

ADDITIONAL INFORMATION
It looks like okular took the png, rasterized it to create the stamp and then placed it in the document tiny.  
It would be very nice to be able to hold down the shift key (like in many design apps) and fix the aspect ration when dragging a corner handle on the stamp with the browse tool.