I've watched 6 YouTube sites by photographers and the average return per download was a low of 66 cents and a high of 96 cents per per image. An average of 81 cents per download for images costing $25+ for the consumer.
To make a living you would need nearly 1,000 downloads a month. The average yearly income was well under $1,000 a year.
Is it worth it? Not to me.