You must own or have permission to use everything that appears in your resource.
If you have included images or text from other sources (including Google images), ensure you have permission to use them commercially. Please note that an image being on Google images does not amount to permission. Find out more about where to find images and other content that is safe to use here.
You will also need to ensure that you attribute the materials you use correctly. Find out more about correct attribution here.
You can read more about copyright, including the Creative Commons licences, in our FAQ pages.