Large Image Blocker от Kai M.

This is a simple extension that blocks images exceeding a user defined file size.

Large Image Blocker helps you to:
- save bandwidth
- increase performance
- save ram

If an image is blocked you will see an alternative text defined in the HTML alt-attribute. If the alt-attribute is missing, you will see a broken image symbol. But there is no placeholder of the missing image at all if it is integrated as a background-image or has neither an alt-attribute nor HTML dimensions.

Note: Images that are already in the browser cache are not blocked.

Known issues:
- Downloads ("save image as…") are affected, too.
- Blocking does not work when the url of the tab is directly pointing to an image. So if you right-click on a blocked image and select "view image", it will be displayed as usual. (This seems to be an issue in the firefox extension api.)
- The extension relies on the HTTP Content-Length header field. A few websites do not set this field so that blocking does not work there.