In the mid 90s I was obsessed with using my old Cannon 350D to capture images and sell them as royalty-free photos on sites such as iStock. In those quiet days, you could make about $10 per image sale and I often made about $800 a month, which was welcome passive income that lasted for years.

I had friends who made thousands of dollars a month selling lifestyle images, so they could rent props and models for a shoot, knowing they would quickly recoup their expenses.