Starting with version 3.5.x, I've had issues with digital photos (.jpg) not loading, all of these images worked in pre 3.5 installs on Windows 10.
I just installed Emby 3.6.0.74 beta on my Windows 10 system to see if this has been fixed upgraded from 3.4.3. Here is an example when I go into Home Videos & Photos and click on a folder containing photos. It doesn't matter if the images are nested in a sub folder. IMG_5284 below will never display in emby. If I reinstall version 3.4.3