I have a Synology station in the basement that supplies my "frame" with videos and pictures. Video streaming and slideshows of photos are absolutely no problem. Tested video formats are .mkv .avi. and .mp4. I cannot give any information about other formats. There are various options for slideshows of photos. Speed (slow, medium, fast), cross-fade effects and also resizing of pictures. Not luxurious, but for my purposes it is perfectly sufficient...

I can't say much about the NAS, except that as far as I know it is not possible to access it directly from the TV. The photoslideshow option is unfortunately still not available, which is a total NOGO for this type of picture frame TV.