Getting Screen Shots - for a PC , for a Mac [shift+command, then hit 4], use SMART, Promethean Software, Screengrab or Awesome Screenshot Add-on's for your Internet Browser
Digital Image Sizing Information
Pixel Dimension (width x height)
Small to Medium
300 x ???
Medium to Large
400 x ???
640 x 480
800 x 600
1200 x 900
Resolution - Resolution refers to the pixels per inch required for good reproduction. Most output devices such as printers are geared in dots per inch (dpi). Computer screens and programs are oriented to pixels per inch (ppi). Generally, the higher the resolution (the more dots per inch), the finer the detail and the larger the file size.