Bugshot is a great tool for iOS developers, beta testers, and bloggers -- or anyone who likes to draw arrows on things. Normally, when I take a screenshot that needs to be annotated for a blog post about an iOS app, I move the screenshot to my Mac and use Preview's annotation tools. That process has just been sped up with Bugshot, because I can now make quick annotations on my iPhone or iPad and skip Preview altogether.
Launch Bugshot and you are presented with thumbnails of the photos in your iPhone's or iPad's Camera Roll. Tap one to select it and you'll discover that Bugshot supplies only three annotation tools. That's a far cry from what you get with, but I like the simplicity here. You can draw arrows and rectangles, and there is a blur tool. The arrows and rectangles are orange and only orange; you'll need to go elsewhere for a color palette.
It's easy to resize arrows and rectangles by pinching, or repositioning them by dragging with one finger. You can't change the angle of an arrow you've drawn, but it's easy to double tap to remove it before you make another attempt.
Tap the button in the upper-right corner to save your annotated screenshot to your Camera Roll or share via e-mail, Facebook, or Twitter. You can also open it in a number of apps, including Dropbox, Evernote, and Google Drive.
For quick annotations, Bugshot is great. For more tools, including the ability to add text to your screenshots, give Skitch a go.