This image is NOT in an external file. It is part of the html page.

img alt="" src="data:image/jpeg;base64, ####Base64 Encoded Image####" border="4"

This is an example of the data: URI property/scheme

This only works in mozilla browsers. For IE you have to use its .mht archive files.

This is the tech behing unipage which was featured on slashdot.