First, thanks for using VR Gallery!
I will attempt to place all common questions that I get in this thread.
Q: When I load a folder with a large number of images, the HTC Vive Home screen is displayed, and the application seems to have stalled. What is this problem?
A (short): It will take a long time to load large folders. There should however be a loading screen presented every ~10 seconds with status information.
A (long): It takes a long time to load an image (up to a second for high-res images). Unity has no means of doing this in a background thread. This means that the images need to be loaded on the main thread (that renders the GUI). HTC Vive shows the home screen if too many frames are dropped. There were essentially three (bad) options to choose from regarding loading images from the disk: (i) present no status updates what so ever, (ii) halt the loading every X seconds and present a status update, or (iii) present continuous status updates but with the price of enormous lag (switching between the HTC Vive home screen and the application renderer every ~300ms). I chose option number (ii).