ImgLikeOpera allows load only the images that you want in Firefox browser.
This extension is very useful for non broadband users.

Features:

 * placeholders for blocked images (hi, LJ treads!);
 * (re)load image from context menu or Ctrl+rightMouseClick;
 * forced expiration time (5 minutes - 3 months);
 * one of four policies for each tab:
   o don't load images;
   o load cached images only;
   o load images for the originating Web site only;
   o load all images.
 * filters.

WWW: http://imglikeopera.mozdev.org