For Drupal 7 and beyond
This module shows images as dummy images. If you are working on localhost or a dev server you do not have all the images from the production server - this is the module for you.
To install, enable the module and go to admin/config/development/dummyimage and configure in which cases you want dummy images to be used. You can also adjust
dummy image appearances there.
For Drupal 6:
This module shows any image that would have been displayed by imagecache as a dummy image. If you are working on localhost or a dev server, but you don't have the images from the production server available, this is the module for you.
To install, enable the module and go to admin/build/imagecache/dummyimage and tick the "use dummy images" box. You can also adjust dummy image appearances there.
Services
This module gives you the choice between these 4 placeholder image services:
The awesome dummy image generator service made by:
Russell Heimlich (@kingkool68)
http://dummyimage.com/
The fabulous http://placekitten.com service that will make your site full of cute Kittehs.
Don't like kittehs? Fine, be weird! And use the almost as fabulous http://placedog.com
The great http://lorempixum.com - gives you random images from categories you choose.