Hi @catrina418,
Greetings from the Roku Community!
We understand you are having a problem with the Onn Roku TV since the pictures are showing dark. We're happy to help.
Please try to restart your Roku TV by going to Settings> System> Power> System restart.
If the problem persists, we suggest contacting the TV manufacturer. Each Roku TV manufacturer provides direct support for its products running the Roku OS.
Hope you'll find this info useful.
Best,
The Roku Community Team
John
Roku Community Moderator