Question Attatch files for upload to forum default location

[BTRY B 529th FA BN]

I've done a little searching but couldn't find anything on this. Every time I upload a picture to a forum via the 'Attatch File' method Windows randomly opens up different locations. Sometimes Documents, sometimes Desktop, everywhere but where I want it to consistently open up at. Is there a way to make a default location for every browser to open up at? e.g. say I want explorer to always open up the Downloads location, how would I do that?

Thanks