New York-based Fotolia says it is the largest microstock agency, with nearly 2.3 million images in inventory. Fotolia attributes this growth to the high contributor commissions, which it says averages 50% of the sale price. The company also says that it generates the highest revenues for its photographers, with top producers netting between $12 and $36 per image per year and net revenues of $5,000 to $10,000 per month.

Previously, the only evidence of six-figure incomes solely from microstock has come from iStock's Lise Gagné and Yuri Arcurs, who runs a stock production agency and sells his output through a number of micro-payment sites.

Fotolia's figures suggest that a larger number of microstock shooters make a respectable living of over $60,000 per year. However, the recent PDN Stock Income Survey paints a different picture, calculating the average annual revenue of a microstock photographer as less than $4,000. Almost 60% of the 865 microstock photographers participating in this survey reported earning less than $1,000 per year.