Where to place my button to open a full screen gallery in my design on iOS?

I need advice to placing a button or an icon on my design. The button/icon should open a full screen gallery. I have a few ideas mock already like press the image or press a button.

The problem with this 2 ideas is in booth test cases the user is always confused and doesn't really know how to open the gallery.

I am looking for any suggestion's

here's the mockup