The Gallery application is nice but it does not compare with the Samsung Frame offering and that's too bad because LG could through software be quite competitive. One place to start would be to look at the Art Legacy+ and associated applications available from a small company called Landka. I've displayed from an iPad their 100+ classic images. Each image is panned slightly during display so there is no danger of burn in. Images can persist for up to 60 seconds (would rather see up to 10 minutes). The cost is minimal. LG could look into licensing this app or doing something similar. The app itself could also use a couple of improvements: 1) an optional virtual frame such as is offered by Samsung Frame and 2) changing the background color of the TV where the image does not display (for example a vertically-oriented piece of art) to be much more like a matte around a photo.
I'm running Legacy+ on my LGTV daily. It really improves the room and adds a lot of value to the TV.
