I'm wondering if the background on my "Trip to the Beach" picture had a transparent BG or not... If not, does anyone know how to make the background of the images uploaded transparent and not black? What type of file should it be saved in? (I save mine in PNG, which works to have a transparent BG on deviantArt, but maybe that type of file doesn't work on this site?)

Please help! It's greatly appreaciated!! <3