ente photos not 'registered'?

Okay so I'm not really sure how to describe this, I use graphene and ente for my photos which works great. On my phone, when I go into Signal or WhatsApp and try to attach a photo, I don't get ente as an option for where to get photos from so I can't get to my gallery in that way.

Is there a thing I need to do to tell the os that ente is the place for photos?

Thanks!