Cropping with PM is easy and stright forward. First, open "Preferences", and select "Preview". Look on the left side towards the bottom. You will see the cropping section. Set the sizes you want as the default and decide if you want "constrained" cropping. Click on OK.
Then, when you open an image in preview, look on the left side, middle of the screen. Click on the "Crop" Botton. Once you have done this, the cursor should change into a "crop" tool (this may have an official name, but I am not sure what it would be). Once you have done this, click and drag the crop tool over the area you want to crop. Don't worry, you can adjust the positioning of the crop after releasing the left click. The portion of the image that will be cropped out is darkened. Then, simply go to file, save as..., and save the image with a new name or extension. Don't worry, vertical and horizional images will be cropped correctly, as PM automatically converts the default size to fit the orinatation of the image.
This is very basic and I know Kirk could explain it much better, but I hope this helps.
Bruce
