How To Make a Ragged-Edged Frame (in Photoshop)
There are two major parts: PART ONE - make the frame and PART TWO - apply it to your photo.
PART ONE - Making the frame
Step 1 - open a new photoshop file (file -> new) and make it as close as possible to the dimensions of your photo. (I used 7 in x 5 in 300-ppi RGB 16-bit TIFF because that's the format I save all my images as, but you may be different...) The background must be WHITE.
Step 2 - set your foreground color to Black and select the rectangular marquee tool. Draw a rectangle on the white background (but leave space - don't use up the entire size of the image). Click on the paint bucket tool and then click once inside the rectangle to fill the rectangle with black. Now Select -> Deselect (ctrl-D on a PC) to deselect the rectangle.
You should now have something that looks like this: FIGURE 1
Step 3 - Select the brush tool and find a brush that will give you the ragged edge. HINT - the dry media and faux finish brushes work well, but you sometimes need to make then larger in order to get the effect you are happy with. Use the little arrow next to the pixel size in the brush toolbar to append more brushes if you don't see the ones you are looking for. (For the purposes of this post, I used the 39 "rough ink" brush and increased the pixel size to 98).
When you have a brush you are happy with, click once right outside the top right hand corner of the black box. HOLD DOWN THE SHIFT KEY and then click right outside the top left hand corner of the box. You should now see that your brush has drawn a straight line right across the top of your black box. DON'T LET UP ON THE SHIFT KEY and repeat the process of clicking outside each of the remaining corners of the box.
You should now have something that looks like this: FIGURE 2
If you are happy with the way the edges are ragged, then go on to the next step. If not, then un-do what you just did and keep experimenting until you find a brush and a pixel size that make edges you like. This is the hardest part and took me the longest, because I was picky about how I wanted the edges to look.
Step 4 - Use the crop tool and crop away most of the white outside the black box - you only need a very thin strip of white. Now save your file, but don't close it.
PART TWO - Adding the Frame to the Photo
Step 1 - Open the photo file you want to use. You should now have two open files (the photo and the frame) and you should be able to see both of them open in your PS workspace.
Step 2 - Make the frame file the active one by clicking on it. Now go over to the LAYERS palette and click and drag the Background Layer from the frame file onto the Photo file. (the Layers palette is commonly found in the lower right hand corner of your screen)
Your photo file should now look like this: FIGURE 3 and the layers palette for the photo file should indicate that you have a background layer and a Layer 1 layer.
Step 3 - Double click the BACKGROUND layer on the Layers palette and turn it into Layer 0 (accept all the defaults in the box that pops up and click okay).
You should now have a Layer 1 (the black frame) and a Layer 0 (the actual photo).
Step 4 - In the Layers palette, click on Layer 1 and then click ctrl-D (on a PC) or Edit -> Transform -> Scale on a Mac (I'm not sure of the keyboard shortcut for the Mac, so I did it from the Edit toolbar at the top). Your frame will now be selected and you need to drag it to completely cover the photo by using the little square boxes at the corners of the selection marks. When this is done, hit Enter to deselect.
All you should be able to see now is the black frame layer - none of the photo should be visible.
Step 5 - Now go back over to the Layers palette and click and drag Layer 0 to the top of the list of layers.
Step 6 - With Layer 0 still selected, change the layer type from Normal to SCREEN (in the little box at the top of the Layers palette) and you should now see the finished photo with the frame applied. Everything that was black will now show your photo and everything that was white will remain white.
Your finished product should look like this: FIGURE 4 .
If your white border is uneven or too small, use the crop tool to select the entire photo and drag the edges out until it looks right to you.
Step 7 - Flatten your Layers and save your file and you're done!
I hope this makes sense...I do a lot of technical writing at work, but it's mostly dry boring stuff like how to configure firewalls and routers or how to install and configure software on servers. This is the first time I've ever tried to describe stuff I do in Photoshop. If you have questions, just PM me and I'll try to help.
Once you have the basic border down pat, you can try different brushes for different effects. There are thousands of free photoshop brushes that can be downloaded from various sites on the Internet that will give you all sorts of effects. (the frames on the flower photos I posted the other day didn't have the black box, I just used a very large brush freehand and painted with various large brushes until I got what I wanted.)
I hope you enjoy.... :)