When it comes to cropping images the actual crop of the image is pretty much in the eye of the beholder. The one aspect though that you need to pay attention to when cropping is making sure you crop proportionately. Very important when it comes to square icons. It’s frustrating to see what would be a good icon disproportionate. What I mean is you don’t want to take a crop and the image is 105 x 101 pixels…so you just resize it to be 100x100 taking off the constraint options in PS. Even it seems like a small amount of stretching or shrinking…it still stands out. There are two ways to crop in PS. Both allow you to crop proportionately. Cropping Tools
Marquee toolMethod 1: Crop tool
You can basically drag your mouse and create any crop area you want. If you hold down the shift key while you use the crop it will drag a square around the area to be cropped. If you’re cropping for an icon – use the shift. We want a 100 x 100 pixel icon i.e. a square icon.
You can crop out a square area you want (no matter what the original image size is). After cropping the image go into IMAGE SIZE in the menu bar and reduce the pixels to 100 x 100 and there’s your icon (plus any work you’re going to do to it.)
You can also determine the specific size by changing some options in the Options Bar at the top of the screen.
With the Crop Tool selected, if you look up in the Options Bar at the top of the screen, you'll see a Width and Height option where you can enter in the exact width and height you need. If you wanted to crop an image to a 6” x 4” proportion you just type 6 in into the width and 4 in into the height. Drag your crop mouse over the image and it will keep the proportion you’ve called for. Double click in the image and there’s your crop.Method 2: Marquee tool
The marquee tool will also allow you to select an exact size. In the options bar at the top of the screen you can select "Fixed Aspect Ratio", and change the proportions to 200x300 or whatever pixel size you want.
Drag the mouse over the area you wish to keep. If you don't get exactly what you want, you can select the area inside the dashed lines and use the arrows or the mouse to adjust the area.
Click Image > Crop from the main toolbar.