The other day, when I tried to specify in my blog template a 12px-by-12px background image and have it repeated horizontally and vertically, I did something wrong and couldn't get it to work. But I tried again and did it successfully. It looked sort of neat (especially with the new masthead photo, as the few who saw it when I displayed it briefly can attest), but the text was less legible than with the dark slate gray background.
If you want to learn more about using a background image, let me know. It's a very simple matter of CSS coding (cascading style sheets, which blogspot uses). In fact, here's the code, for specifying the <body> tag, that invoked the background image:
background-image: url(http://3.bp.blogspot.com/_o3nHqz3ofwI/RZcYAG81sHI/
AAAAAAAAABI/KXgs97GAb5w/s320/C49645B.gif);
background-repeat: repeat;
The URL is just what blogspot told me after I uploaded the background image (C49645B.gif) to a temporary post.