As part of our introductory Cell Biology course, our students acquire images through microscopes using consumer cameras with memory cards. They then transfer the images to a computer and prepare them using Adobe Photoshop Elements.™ An important part of this process is learning to apply a scale bar, which calibrates the specimen image. Photoshop Elements is a relatively cheap and widely available software package that easily accomplishes this task for anyone who is using a camera system or software that does not automatically apply a scale bar or calibration data to the image. The instructions and figures herein refer to Photoshop Elements version 4.0, but they apply to other versions of the software.