When I select a face on my mesh in the 3D view window, it causes my texture image in the UV Editor window to be replaced by my background reference image. Why might this be happening?
Because that face has that image assigned to it. When you have face(s) selected and open/select an image in UV/Image editor, it gets assigned to those face(s). It’s called “face-assigned textures” and can be used in materials, but their primary uses are texture painting and baking.
Thanks Stan