The Free Dummy Image Plugin replaces a tag within Joomla content (or a Joomla Custom HTML-module) with an image, without having to create, upload and apply any image in your Joomla site.
It allows you to develop, prototype, design and/or test the usage of images in your web site quickly. The Dummy Image Plugin helps you speed up the process of setting up a layout for your Joomla site, including images.
Using the color settings in the Plugin Parameters will help you test the images in your site in a basic color scheme that matches your template.
This extension requires (free) registration to download