Ever wanted to tweak a photo, but have no idea how to use Photoshop? Try Picnik! It’s a free web-based application that requires NO sign-in (woo-hoo!). The basic version has some pretty great features: sharpen, crop, rotate, red-eye correction, and exposure. The interface is very simple and easy to use. Using the “Create” tab, you can add borders, stickers, and text, though many of the more fun features are available only for “premium” users (ie, those who pay for a subscription). If you just want the basics, without downloading any software, Picnik is great.