How do I add a custom background image to my Tumblr?

How do you add pictures OVER your tumblr background? More info in descirption.?

• Im trying to customize my tumblr theme and i was on a few tumblr blogs and i saw that they have pictures over their tumblr background. like png files or something. I have a code for it which is "<div style= “position: fixed; bottom:0px; left:0px;z-index:-2; “><img src=”IMAGE URL” alt=”le” /></div>" but i dont know where to put that. I honostly hope im making sense right now because i really want to learn how to do this.

• Answer:

  you can try and stick it into your info box. it obviously shouldn't show up in the info on your blog. i've put a few code things like that there and they work fine. it gets more complicated when you have to find out where to put it in the html aw i'm sorry :c wait I'm looking it up now http://tumblring.net/how-to-put-a-background-image-in-your-tumblr-theme/ this may be helpful