Setting QField for 1:n photos

I think the problem is your configuration of your referencing (child) layer "photo". your screenshot shows how you configured the uuid field of this layer, but that does not really matter. important is how you configure your "fkid". there you should set the widget type to "relation reference" , and set the display expression to your relation ("photo_718_fkid....")

your "path" field seems to be correctly configured, although I indeed use under "integrated Document Viewer" the type "Image"

So, I've found the cause of the issue: [Project properties]_[Project Home] must be blank.

Also: No need to set the 'Referencing Field' (aka foreign key, i.e. fkid in my example) to a Relation reference. I have Relation set to 'Association' strength - I have not tested 'Composition' strength.

O