DeIMG

DeIMG (was That's Not a Picture) converts images into intricate HTML tables. This application allows Web authors to offer superior support for users who rely on browsers which support tables but not images.
PNG, TIFF, JPG, GIF and PDF files can be imported and converted to HTML, XHTML or XHTML+CSS.
Drag the image file onto DeIMG's icon, or into the image well on the left of its window.

A HTML table describing the image using cell background colours appears in the right-hand field. A large image may take some seconds to translate.
The resulting table can be copied and pasted into a webpage's source. Alternatively, the "Generate header" option creates a stand-alone HTML page.