I am trying to take a sqaure photo and create rough/torn type edges as

the border.

I did this in PSP7 by opening 2 images ...
I would add a mask to imageA by Mask>New>From Image.
Is there a similar way to do this in CS?

Yes ... if the two files are the same size you can do it easily ... open both files ... with the image file active do Select > Load Selection and you should see an option to load a channel from the other opened image. Load it and you'll have a mask, then do Edit > Fill and for "contents:use" you can select black or white for the borders, or any other color if you want something else.

I have tired to use the filters and can not find the look I want.

If you want to play around with this a bit and try looks other than what you have in your picmask.jpg image you can do these steps and make your own mask ...

1) use the rectangular marquee tool to select the inside of the image .... the torn borders will go outside this selection ... alternatively, you can add canvas with Image > Canvas size if you don't want to "eat" too much of the image.

2) with this selection do Select > Inverse then Select > Save Selection and give it a name like "mask" or whatever ... this creates a new alpha channel. Type cntrl-d to deselect.

3) go to the Channel palette and click on the last channel (the one you just made) ... you can rough up the edges of this with filters to create different looks ... not too bad an idea to duplicate this one and work on copies ... to rough up the edges run a filter on that channel, for example try Filter > Brush Strokes > Sprayed Strokes and play with the sliders. There are about half a dozen or so filters that work well with this technique.

4) once you have it roughed up to your taste go back to the Layers palette and do Select > Load Selection and load the editted alpha channel as a mask ... now do Edit > Fill as described above to create the torn edge look. If you know your images will be the same size you can make several different masks and save them off for easy access later.

Bill

CD

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How to create rough edges on a picture with another image