Tumblr Theme Repeating Background Options

[xMorningstar]

Just recently running into a problem with my theme customizations in tumblr.
I've attached my code so you can help me out with specifics, but what I'm trying to do is replicate every image post as the background of the page behind or beside it.
Something like this, but not quite. He has the posts aligned to the left and the background just does "repeat-x"(which I can't figure out how to do because it's tumblr and I'm completely lost), I want the same but just with my original post centered or if it has to stay aligned left to make it symmetrical I don't care. I'm not sure how to get this to work though, just posting the tumblr code for a text post within the page background content didn't work, and adding repeat-x; to the css under Block:posts didn't work(assuming it could just replicate the post rather than using the image as the background, at first I thought if I somehow did that and added overflow to the css so they wouldn't wrap it might work, but no dice), so I need some help.

If you can't tell from that link, it's more than just adding a background, I need the page to read a separate image for every post and repeat it, so every post would have to be like..

{block:xxxx...
<div xxxxx...
<img src="{PhotoURL...
<javascript that somehow fetches the image name...
{/block}


But since the original post and the background shouldn't overlap, I think it's more complicated, idk, if you can figure this out I'd really appreciate it.