Photos.onedrive pops up unexpectedly

I am new to OneDrive.  I just uploaded all files recently and feeling my way along. When I am on my PC's desktop and go to certain apps, for example Facebook or eBay, when I close, I return not to the desktop but to a tab screen of my OneDrive Personal photos.  To get back to the desktop I must close that screen. This is bothersome because it is distracting.  Is this happening due to a default I can change or disable? Thanks very much for any help or suggestions.