Error when upgraded PHP from 7.4 to 8.0

I think I found a cause for this problem.
When you mentioned 'resize', I went into the site and removed all thumbnails (in the folders 'th'). Then did another try on the homepage and got the same result as before, but now, when checking the thumnails, all resize stopped when reaching a .MP4 file among the pictures/media..
Before upgrading to PHP 8, it work just fine having an .MP4 file among the pictures. That was the main reason for me to choose Mediabox CK.

thank you for the information !
I need to test that by my side, I wil let you know
CEd

I have tested, you can remove the error : go in the plugin options >> gallery options >> auto create thumbs >> NO
then the error will disappear. I check by my side to improve that point

Thank you!
It takes a little bit longer now for the user the image thumbnails are locally created, but I can live with that for now. The main thing is that it works as expected. Thank you!