A. Unfortunately, your assumption is wrong. Google is not a stock image library and above each image it finds, you will see a message: ‘Image may be subject to copyright’. The only copyright-free images I know of on Google are if you use advanced image search > labelled for commercial use.
This article gives more background and there is more useful info here.
For affordable copyright-free images, I use stock photo libraries such as iStockPhoto, BritStockPhoto and Clipart.com.