A while back I started using the software "Jing" to incorporate images into discussion here at MFO. Recently rjb112 asked about it so I thought members (new and old) would like to utilize this helpful tool.
Jing is a screen capture tool. It also allows you to add simple graphics (text, shading, arrows, color) to the screen capture.
The screen capture image can be saved and viewed in http format (a link) or as HTML format (as embedded code) within a discussion. Once the image is captured and saved in Jing the html code can be added to a discussion thread by merely pressing the (CTRL) + (V) keys together.
Watch the overview video on Jing's website and if you have any questions let me know.
Free download here
Jing also has a video capture feature which allows the user to create a "live screen capture" with the additional feature of adding audio. It's basically a movie using your computer's screen as the video capture and computer's microphone as the audio capture. Not sure if MFO is ready for this, but I find it really a great tool for demonstrating a topic with audio.