Ask any accustomed photographer, and they will tell you that people images sell the most and they continue to experience record sales. The beautiful thing about images that feature people is that their demand will only increase moving forward. So the possibilities of selling them are great.
When taking free images for websites, make sure to leave room for typography
Today, image buyers want to do a little manipulation (adding title and texts) before they use them. These kinds of buyers will only buy images with plenty of space on the right or left-hand side of the image that allows extensive manipulation. So, when shooting your royalty free photos, be sure to take note of that.