how do you "undo" something you've done on a Galaxy 5?

[AC Question]

a dialog box popped up while I was uploading a picture to a forum. a notification box kept coming up and I was tired of seeing it and so i clicked on "don't show again" now I realize that i need that box to post other pics and even to post link on other sites but I can't find where to do to reverse it.
any help would be greatly appriciated.

thanks