How to force a web browser to cache Images

Question

I am writing a small application which serves images from the local computer, so they can be accessed as http://localhost:12345/something/something (which returns a jpeg). <

Answer 1

A Last-Modified and Expires header might also be useful additions.

Your server should also check for requests featuring an If-Modified-Since header, and return a 304 Not Modified response if possible to speed things along.