Hi everyone,
Magnus was very kind to implement an idea that consists of two parts:
1. use of WebP (http://en.wikipedia.org/wiki/WebP) instead of PNG/JPEG for thumbnails in Wikipedia articles 2. use of Data-URIs (https://en.wikipedia.org/wiki/Data_URI_scheme) to inline incluse those thumbnails.
The experiment can be watched using Chrome and Opera browsers at http://toolserver.org/~magnus/wp_data_url.php?lang=en&title=Albrecht_D%C...
Firefox and other Data-URI capable but currently WebP incapable browsers can watch the second part of the experiment at http://toolserver.org/~magnus/wp_data_url.php?lang=en&title=Albrecht_D%C...
Base64 encoding has a ~1/3 overhead. This overhead is reduced when the server sends out gzip files.
Mathias