Why does my galaxy S6 keep asking me to rename my saved photos everytime I try to save an image

[ShaneD7SD]

Everytime I save an image it asks me to name it, I don't really have a good sense on how to do this, I want it to stop because now its saying the image may become unusable and after instead of saving image it says file downloaded for some reason I can still view it in my galary but its annoying to have to do this everytime