Let's say you are browsing and see something you want to copy on the web, left-click on the aviary icon to bring up the menu options.
Click on the "Capture Visible Portion of the Page" (or Capture Entire Page).
This will open up a new window with the Aviary image editor and your webpage selection.
As you can see there are a plethora of tools for editing your image. My favorite is the cropping tool:
Once you crop and edit your image you can save it online with many options, you can even share right to twitter.
I like to Copy the Image URL. This way, I can take the image and render the image online to paste into Gmail messages. (See my other next blog post for information on how to do this.)
By the way, I used Aviary and the steps I outlined to snip all of the images in this blog post.