I'm having a similar problem with a Galaxy S4 GPE, which I thought was tied to the 4.4.4 update, but now I'm not sure.
When I go into the Gallery, it shows most of my folders correctly, but one folder only has a blank tile. The next couple folders show ok, then the rest of the tiles after that are blank.
If I go into a folder, most of the time the tiles are blank, even if the folder showed an icon.
Most of the images are on an SD card, and when I pull the card to look at the images on my PC, they all seem fine, and I haven't had any errors loading the card on the phone or the PC.
This happens in both Gallery and Photos, so I'm assuming it's not related to the card-- something ES File Explorer has no issues with it.
I've tried both clearing cache and data for Gallery and Media Storage, as well as rebooting immediately after clearing that data, and I've tried using Scan Media and Rescan SD to repopulate the data, all with no luck so far.
The only thing I *haven't* tried doing so far is selectively pulling out folders to see if there's bad content in there somewhere that's messing up the whole process.