As long as they are labeled for commercial use, you can use stock photos in multiple designs and projects with a for-profit purpose, including websites, marketing and advertising, branding, and more. If the photos are labeled as Editorial, you can only use them for this end (never commercially).
What is the purpose of stock photos?
Stock photos can be used for marketing and advertising, personal projects, commercial and for-profit projects, and on blogs and websites. The wide variety of uses and instant turnaround time make stock photography a common choice for independent graphic designers and businesses alike.