For some reason transparent files don't work on this site, they always produce a white rectangle. Instead, I create a jpg with a background that is matched to the background color of the website. If you'd like to know, the RGB color is 248, 232, 231, and the hex value is F8E8E7.
EDIT* Please ignore, I found the answer in a forum area Hey Tain, I have a quick question, what format do you save your images in so that the background is transparent? I tried .gif and .png but those didn't work.