If you use Dropbox, you will also get prompted to automatically save screenshots to the Screenshots folder on Dropbox, and a link to the latest saved screenshot will be copied to your clipboard, so you can instantly share that image with others if you need to. Your Mac comes with an inbuilt screenshot facility that is accessed via keyboard shortcuts. I take a lot of screenshots on a daily basis for various uses, so I make sure I use the best tools for this purpose.
