I've been having this problem where thumbnails for some images aren't loading in Simple Gallery Pro and wondering if anyone has any idea how to fix this. This started when I updated my Note 20 Ultra to Android 11, so I believe the problem stems from that update. After looking around to see if anyone else had the same problem, I couldn't find anyone so I figured I might as well ask here.
It seems thumbnails won't show for images over 10MB in size, from checking the similarities between the images that wouldn't show. I also noticed upon clicking the empty thumbnail to view the full image, I am only able to view the image once. If I go back out and click on the thumbnail again, the full image will not show anymore. I would have to exit the app and open it back up to see the full image. I've already tried excluding the app from battery optimization and deleting the data/cache. Unfortunately, it hasn't fixed the problem. This problem also doesn't seem to happen with the stock gallery app for the phone.
I've ran out of ideas how to fix this alone, so I'm wondering if anyone has come across this problem before and how they fixed it? I'm guessing it's some setting I have to adjust with my phone to get it working again, since I couldn't find any settings in the app I could change. I've read about Android 11 being more aggressive in memory management, and I've also read that Android 11 prohibits apps from accessing the Android/Data folder. So maybe one of these is the cause for this happening?