I'm having a similar issue to this, but with the new Photos update that just installed for me in the last couple days. Any time I open a new image from Explorer, it opens all the image windows that I have and brings them to the foreground, even if they're minimized or behind other windows.
Obnoxious and extremely intrusive. I often need multiple images open in the background and to open new ones here and there without everything coming to the front and getting completely in the way.