Why not use CSS to repeat it then you can shorten it to something like a 50px x 50px square or a 1px by 1000px then just repeat the background left to right, top to bottom or both if it is a pattern, that way the file will only be a few bytes and load with in a millisecond, but still give you the same design.
Do you have an image we can look at?
Also if it is a .png have you compressed it as that tends to cut about 75% of the image weight down, makes it uneditable so make sure you save a back up copy first to make amendments later.
Jaz