After a day of shooting pictures, you may discover you have an image you would like to use online, such as for an avatar on a social networking site. Digital photography allows you to decrease the size of your images using a photo editing program. The software lets you crop the image to a 50-by-50 pixel square from its original rectangular shape.
Turn your computer on and open the photo editing program you use to edit your pictures. Remove the memory card from your camera and insert it into your computer's card reader.
Download the images to your computer's hard drive. In the photo editor, click "File" and select "Open" from the drop-down menu. Use your computer's cursor to navigate to the folder containing the image. Highlight the image by clicking on it and click "OK" to open the image.
Select the crop tool in the photo editing program and choose a size of 50 pixels by 50 pixels. Change the dpi (dots per inch) value if the website to which you will be uploading your photo has a maximum resolution. Some require an image to have a resolution of 72 dpi. Pictures typically are printed on paper at a much higher resolution, often 300 dpi.
Position the cursor at the bottom left position of where you envision the bottom left corner being in your cropped photo. Draw your computer cursor up and across the image until you reach the top right position for your enlargement. Double-click your mouse, and your photo will be cropped to your settings.
Click "File" and select "Save as" from the drop-down menu. Give your picture a new name so as not to overwrite your original and save the picture to your computer drive.