Be careful: most Creative Commons images require attribution, meaning you need to give credit to the artist in order to use the image. Make sure you understand Creative Commons and other licenses 3 Popular Image Licenses You Need To Be Familiar With Before Using Someone's Photos 3 Popular Image Licenses You Need To Be Familiar With Before Using Someone's Photos Read More before using such images.
This is TERRIBLE! Besides being able to edit vector images like Will mentioned (which is important for those of us who don't have graphic artists available to create custom images or the budget or time to buy that service ad hoc), you could also search for style "families" (different graphics that were all in the same style). There was a huge range of files and styles in the collection and it was much faster to find what you need than to do a Bing search. Plus, you knew that everything there was free and free to use, without having to worry about CC license issues.