JIRA allows you to paste in screen shots while editing. Confluence can benefit from this as well

As a UI design consulting company, we typically email screen shots to each other and comment on them. Snag IT is a common tool we use. Take a screen shot, paste it into your email message and then comment on it. We commonly have multiple images per message.

JIRA has the attach screen shot link that would be nice to see inside confluences editing tool. You click that link in the toolbar, the new window appears where you paste from the clipboard and ass the meta data, when you save, you see the image appear inside your editing window.

For all the reasons the development and QA community wanted to have a paste screenshot inside JIRA, the design and requirements community will want something like this inside a wiki.

I find the image image toolbar button to be overloaded. It would be nice to has one for adding an image and another for editing an existing image... but I kept the existing constraints as I worked this into my sugestion.