I'm not sure what you mean by "install", but...
If you talking about adding pictures to a screensaver, then you want to try Photo Streams:
How to use Photo Streams on your Roku® streaming device | Official Roku Support
If you want to view them from a USB drive (if your device supports it) or a NAS (if you have one) or a computer:
How to use Roku Media Player to play your videos, music and photos | Official Roku Support
If you want to view them from a phone:
Ways to display media from your phone on your TV using a Roku® streaming device | Official Roku Supp...
Roku Community Streaming Expert
Help others find this answer and click "Accept as Solution."
If you appreciate my answer, maybe give me a Kudo.
I am not a Roku employee.
