Hi mangosteenG,
Welcome to Apple Support Communities. I understand you added a shortcut from the Gallery of, "Videos to GIF" but you're unable to access the Camera Roll on your iPhone.
Shortcut is a convenient feature to quickly complete one or more tasks. I'll be happy to help.
Based on the error message you're seeing, you'll need to make sure that, "Photos" is turned on in order to allow access of the Camera Roll for "Allow to GIF" in the Shortcuts app. I personally tested this on my device and here are the steps that can help resolve the error message you're seeing:
- In the Shortcuts app, tap on "My Shortcuts" in the bottom left corner.
- Tap on the three dots in "Videos to GIF" to open the shortcuts editor.
- Underneath, "Done" in the upper right corner, tap on the three dots.
- Make sure, "Photos" is turned on in the section that says, Allow "Videos to GIF" to access.
From there, see if you can add photos or videos in "Videos to GIF."
Please let me know if that helps.
Kind regards.