Hmm interesting.  I'd like to figure out what it is then.  I see the square on both my laptop and work computer.  But when i save the image as a png file it opens with a transparency.  What do you think is causing it.  I'm curious because everyone else's transparencies look normal. 

I see a grey-blue background behind all of your pieces.  This isn't a transparency.  If this is your style, so be it.  But I think most of your works would look better without this lackluster backdrop. 

(The link will instruct you on using Transparency in Photoshop.)