We all know about Photoshop’s crop tool, but did you know you can control it down to the pixel? Let’s use this nice colorful image and make a few thumbnails. Let’s assume we will be using these thumbnails on the web, so we have already optimized our image and got it ready to save for the web.
First, in your toolbar select the crop tool. your options tool bar will change, giving you a set of controls specific to the tool bar. (If the option bar is not visible, it might not be turned on. To see it, select Window > Options.)
In the option bar type in the Width and Height in pixels. The crop tool allows Inches as well, so be sure to be specific! px = pixels, in = inches. In this case I want to make 50×50 pixel thumbnails, so i enter 50 px in the Width field and 50 px in the Height field.
Now that I have my sizes entered, drag the crop tool on the desired area of the image to make your thumbnail.
Hit enter and BAM you’ve made a 50×50 pixel thumbnail.
From here be sure to Save As… so that you don’t overwrite the source file. Remember, we have to make two more thumbnails out of this image. A good practice is to make a Duplicate (Image > Duplicate…) before you start editing. Enjoy!