Firefox gives you the ability to block image loading from individual websites (that you define), or from all websites on the Internet.

To make use of this feature, go to the top of your browser and click Tools > Options:

 

 

Make sure you are in the “Content” section.

Below, I highlighted the checkbox where you can enable/disable images:

 

 

In both cases, whether you enable or disable images, there may be some sites that you consider to be exceptions to the rule.

Click on the “Exceptions” button to create a list of sites that you allow or disallow.

 

 

In our example, we’re going to block all images from Yahoo.com. (Nothing against Yahoo! here. This is only an example).

So we type Yahoo’s URL ins the text box marked “Addresss of website,” and then click the “Block” button:

 

 

All images from Yahoo.com are now blocked:

 

 

If you change your mind about this site, or any other site that you add to the list, you can always remove any or all of them: