Commercial use requires 'releases' - editorial use doesn't. Stock photos can be sold for commercial (eg, marketing) or editorial (ie, journalistic) use. You'll have more opportunities to make cash if your photos are available for both, but photos containing people or property (including branding and logos) need signed releases to be sold commercially.
Yet another Amazon service providing the possibility to make money online is the Audiobook Creation Exchange. You can create a standalone audiobook, or create an audio version of your eBook as complementary media. And you can narrate your audiobook yourself, or Amazon can put you in contact with a professional to help. Once sold, you can then earn up to 40% royalties per audiobook.
How much will you make? I think my best month with Google AdSense was almost $5,000 over the last ten years. That amazing month blew my mind since it was actually near the beginning of my blogging journey. When you go from making zero to $5,000 in a month, that will rock your world. For me, it also got me even more excited because I knew there were other ways to monetize.