MattWilcox/Adaptive-Images — pull request #40 by marcaube (2012-03-27 15:47:37+00:00)
Title: Fix image caching

Added the Last-Modified header for images to be cached.

I took code from http://ernieleseberg.com/php-image-output-and-browser-caching/, trying not to reinvent the wheel in the process.

If the image in the browser cache is the same as the current cached image on the server, it responds with a 304.