Creating a 3D border for an image in Photoshop is a tricky business. The best approach is to crop the picture to a specific size, and then manually move the border outward from there. The result is a more symmetrical image, which should be more aesthetically pleasing.
The first step to achieving this feat is to create a new layer on top of your chosen image. To do this, select the Layer menu and choose New Layer. You can then drag the new layer off the left or right side of the image and outwards, whereupon the image window will expand. You can then use the mouse to move the cropped border outwards as well. To get the most out of this exercise, it is worth considering some complementary color options. For example, if your image features an image with a green background, consider a yellow or blue. You could also try out a combination of a red, black, and yellow hue. You will need to choose carefully, however.
To make the task of removing your image from the computer a bit less daunting, you may want to consider using the Extend tool from the Layer menu to make the task even easier. This will allow you to resize your object with a couple clicks of the mouse, which should make the task a snap. This trick is especially handy if you’ve already done the heavy lifting of pixel pinning.
You may also want to take a look at the Photoshop tool bar for more advanced cropping options. There is also the bicubic sharper, which is more of a reduction tool than it is a magic wand. To see the results of your efforts, try the new “View Cropped Image” window that appears when you select it. You’ll also get a preview of the cropped image, which is a definite plus.
The most important lesson of all is that you need to be aware of the differences in width and height ratios to achieve a satisfactory result.