EuroSymphony OnlineClipart allows you to quickly add free images from the Wikimedia Commons collection to your documents.
You need to have an active internet connection to be able to search for and download images. The images are embedded in your document (not linked).
The source of the images is Wikimedia Commons. Almost all of the images can be used freely, but many require proper attribution. EuroSymphony OnlineClipart automatically inserts the images with a caption that attributes the image to the author as named on the Wikimedia Commons page and links to its web page. For many images this is enough, but it is best to check the web page of the image and take a look at the license terms to make sure. Wikimedia Commons has a guide for complying with the license terms of different images.