As you can see in the screenshot, inside the Photo Picker in the Albums view only "Screenshots" is shown while in Photos view all the pictures are available in chronological order.
By looking it up, I foundpeoplecomplainingthesameissue and one suggesting adding them with Google Photos (which I don't have and I don't want to install).
Just wanted to know if someone else here got the same issue or if there is a workaround/fix for this.
(I'm on GrapheneOS)
The point of this dialog is to choose which image to share with the app without giving full permissions. In fact the app itself does not ask for storage permissions at all.
And I can see all the pictures in Photos view anyway, so I don't think it's a permission issue.
Edit:
In installed apps list there is "Media picker" which COULD be this. It does not ask for storage-related permissions.