This is a very simple tutorial but you do need
some plugins...

20/20
Visual Manipulation

First the image that I am going to use for this tut. It is best
to use a picture like this. A picture that has the main part in
the middle. Otherwise the effect doesn't work properly. But
you can try this tutorial on loadz of picture till you find the one
that works for you.



Go to Effects, Plugin Filters, VM Experimental, Deep Crunch and
use these settings (I think they are the standard settings)



After applying this effect, go to Effects, Plugin Filters, VM Distortion, Flipchop and
use these settings:



One more effect.........go to Effects, Plugin Filters, VM Distotion, Flipper and use
these settings:



This should be the result:



To make this a seamless background. Save this picture, open it in 20/20
and in 20/20 go to Image, Tile Effect and your background
is ready :-)