I have wanted a digital picture frame for a while now. However I have not wanted to spend the money for a store bought product and thought building one sounded rather complicated.
After thinking about it for a while I decided using a 15"ish monitor and a Raspberry Pi zero W would greatly simplify the project. It would really just turn it into a few scripts and hooking up a monitor with the pi. If I had tried to drive an LCD panel it would have been a lot more work.
I found an HDMI monitor on FB Buy Nothing. I had a rPi hanging around. I just had to buy a few cables.
FEH does all of the hard work. It can randomize the pictures in a directory tree, delay how long to show them, go full screen, etc. The only thing that made it a little complicated was feh has a memory leak. It took a bit to discover that. Once I had figured that out I just added a loop around feh to restart it after each crash.
FEH memory leak:
Script to run feh. Just point to it from crontab. I stored my pictures on my NAS, and just update them once a month.
feh --fullscreen --auto-zoom --randomize --hide-pointer --recursive --slideshow-delay 20 /mnt/pictures/kids_pics/pics