Patchwork Border

Hello there, first message, as you can guess :D

I'm not totally new to Photoshop, I have some experience of it, but I can't call me an expert. Intermediate user, probably. And I have a problem.

I have a patchwork image like this one (the one I'm working on is much much much much larger with many many many more colors)...

http://img193.imageshack.us/img193/9645/32679448.jpg

...but I need a border at the edges of each color section as you can see in this other one...

http://img36.imageshack.us/img36/4390/34228778.jpg

...but I need a border hopefully made by Photoshop itself through some trick not by my hand :P

If possible, I need a border with hard pixel edges. I created the second pic I posted simply applying a stroke fx to every color selection... I'm looking for a more "automatic" way.

Thanks in advance for any tip!

On a duplicate layer, apply find edges filter. Desaturate. Use levels to max out contrast. Change blend mode to multiply. This could easily be run as an action.

I have a rather old version of PS, you should be able to do as well with a newer version.

1. Start by copying the image and paste it onto a new layer. this layer will become the outline and is where you will be working.
2. In the filters menu , stylize, find edges. Apply the filter to the top (new) layer.
3. Filters menu, sketch, photocopy, apply the filter.
4.To refine the outline use, filters, blur, gaussian blur, setting 2.5 to 3 pix.
5. continue to refine the outline using, filters, other, maximum.
6. Darken the outline with image menu, adjust, levels or brightness and contrast.
7. Use the merge mode, multiply or darken in the layers palette and flatten the image with the layers menu item "flatten".

There may be a better way to do it with a later versions of Photoshop, but thats how I do it with my old version.

Thank you very much for that great help! I cannot try it myself until tomorrow, but that is exactly what I was looking for.

Much obliged!