Google Docs is integrated with Google Image Search to help you quickly find and insert web photographs in your documents. The results are filtered to only show images that have been licensed under Creative Commons and labeled for commercial reuse so you are legally allowed to insert these images in your documents.
Other than Creative Commons, there’s a new image search option available in Google Docs that will help you find professionally shot photographs for your documents. Google has partnered with stock photography services like Photos.com to offer royalty-free stock images inside Google Docs, just like Microsoft PowerPoint.
While you are inside the edit view of a document, go to Insert – > Images – > Stock Photos and use the search function. The collection of stock photographs available inside Google Docs isn’t as big as what is offered by Microsoft Office but that should possibly change once Google signs up with more partners.
Other than Google Documents, the option to insert stock photographs is available in Presentations and Google Spreadsheets as well. Thank you Eric Curtis.