Why can't I save photos on Chrome? (Android Marshmallow)

[AC Question]

When I try to save an image on Chrome, I get the error "Chrome needs storage access to download files." I tap on the "Update Permissions" button and it takes me to the Application Info, I tap on Permissions and when I try to enable Storage, it says "Screen Overlay Detected". To change this permission setting, you first have to turn off the screen overlay from Settings > Apps. Not sure what to do from here. Can someone please walk me through? Thank you!!

Yuki