Forgive the over-explanation of the process for other users who may have this same question in the future...
Here is the standard way of getting images into a question on Ask Patents:
Use Google Patents to find the subject application. Usually the images are listed along the middle ribbon as follows:
In some cases, the patent application is too new and images don't appear in Google Patents even though you can see the rest of the application. In those cases I use Public PAIR to look at the File Wrapper. Note that logging into Public PAIR is a pain... you'll want to search by Publication Number and the number must be copied EXACTLY with spaces and trailing information.
For example, a recently published application "US20130110664A1" can't be found on Public PAIR by searching "US20130110664A1", "US 20130110664A1", "US20130110664 A1" or "US 20130110664". You'd need to use the string "US 20130110664 A1" to retrieve it.
Within Public PAIR you'd want to look under "Image File Wrapper" and look for document type DRW - Drawing Only Black & White Line Drawing. DRW type is a PDF of the actual images sent by the applicant to the USPTO and included in the file history.
I use Jing on Mac and save to the desktop.
Host the Image
Ask Patents uses imgur. The easiest way is to take the image you have saved to the desktop and upload it yourself. Copy the URL from imgur when you do this
Post the Image
You can upload the image from the Markdown buttons on Ask Patents or you can just copy the display image HTML into your question, where the URL is of course substituted by the image URL you have just created:
<p><img src="http://i.imgur.com/y5qvO7E.png" width="400" height="300">"