This technique will show you how you can get a very interesting background effect pretty easily.

Hi, heres a nice sig/ avatar background image 馃榾

Ok, start of with a blank transparent background image of any size u like – im going to do 500×500

Ok, now choose the paint bucket tool, but hold down to choose the gradient tool. Now select the circle shape tool

now choose two colour gradient – with black as one colour. I chose blue. Now set the blend mode to difference at 100% opacity. Now start making random shapes, just go wild with the tool. The more u do the better it looks.

As soon as you have done this go to filters>stylize>find edges

this鈥檒l give u a nice effect :D, but not nice enough

so press ctrl+i to invert the colour (mine is half and half to show u (to do this, lasso around the section u want inverted and press ctrl+i to only invert the selected)

Now, this is nicer. Now to do the matrix effect ontop.

Create a new layer (ctrl+shift+n)

No, fill with white (either use fill tool or press D, ctrl and backspace (if the background is black press ctrl_i again.

now choose filter>texture>grain – with 100 intensity and 50 contrast.

press ctrl+j to duplicate this layer. Now, hide the top layer, and on the original layer, go to filter>blur>radial blur
choose 80 % zoom best quality.

set this blending mode to colour dodge -this really brightens it up.
Now with the untouched matrix layer, unhide it, press ctrl+u make sure colourize is selected and choose these settings:

now all you have to do is choose a layer setting of your choice. I like Hue 馃榾

hope you like. Mess around to choose settings u like. Like inverting the colours after this to give u a nice purple background. Here鈥檚 and example of what you can do.