I'd like to chime in that I too am having this same issue.
Here are my particulars:
TCL Roku TV
Model 65R635
Hardware ID A114X
Serial number X00300KU3KWR
Software version 12.0.0, build 4182-88
Device ID S05FY07U3KWR
Roku Media Player Version 5.5, build 13
While troubleshooting this issue, I have done the following on numerous occasions:
(TV) Settings>Power>Restart
Remove the Roku Media Player
(TV) Settings>Power>Restart
Reinstall the Roku Media Player
(TV) Settings>Power>Restart
Then ... try out the media player on some photos ... no Joy. I get proper thumbnails for the photos but once I select a photo and let the photos cycle through there is just a black screen. Interestingly, the screen will show the file information for each photo as they are cycled through.
Here is a video of the phenomenon:
I have never seen any error message on screen. And the behavior is the same using a USB thumb drive or my DLNA media server. Originally thought it might have something to do with file size (some of my photos were super huge JPEGs.) But I just tried with a handful of very small PNGs. Same result, I get the thumbnails displayed fine, but no luck actually displaying the photos full-sized. Video and music files work just fine from the USB and from the DLNA media server.
Happy to answer any questions not covered here.
rmeineke As mentioned previously, there has been no updates in RMP for close to three years, and even the most recent updates were solely related to music playback. Right now, the only reliable way to play back local media on a Roku is to use Plex or Emby. RMP is simply not functional in many ways.
Both Plex and Emby are free products, and they can be installed on the same computer that is running your DLNA server without interference. They will at least allow you to play your media while you wait for Roku to get around to fixing RMP.
