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Before you get started searching for images to use for your business, let's do a quick terminology run through.
Royalty free - you'll see this a lot! It does not mean free for you to copy & use. It means that once you have permission from the rights holder (and paid an initial fee) you can then use it without paying further royalties.
Best to look for clip art and images that are open resources meaning that the rights holder has granted permission, up front, for how you can use their work. Look for images with a CC-license and terms that suit how you want to use it. In Google, there are features that allow you to filter to images with an appropriate license. Use the Advanced Search feature under Settings, scroll to the bottom and look for the Usage Rights field.
Here are a few good sites to get you started:
