The HTML code for this example is:

< IMG SRC="pete.jpg" LOWSRC="pete2.jpg" WIDTH=364 HEIGHT=500>

The low quality version, pete2.jpg, is 7,401 bytes.
The high quality version, pete.jpg, is 48,952 bytes.

Photograph courtesy of J. D. Cornelius, © 1995

ReaConverter - batch image converter between 400+ image formats.