I would nt go there, the file size will be big and also there is a subtlety to tiles for backgrounds, if the back is loud then people wont look at the site, mb use small leaves and over lay them.
The trick is to make it not so repetitive, what I did was make a copy of the leaf and place it next to it and flip it veritcally. Then I used Photoshop's Inner Glow to both leaves to add a thick black fading border. Then I merged down, and decreased contrast to make it fade to black alot more. Then just compress it highly using jpeg and you only get a 20k background tile which is generally acceptable. It's not the greatest, but used right it could look ok.