Stock Photography - Hobby Income or Business?

I am interested in selling photos online through stock photography agencies. To me this is just a hobby and I anticipate the income to be low and not something I would ever depend on. I already have a full-time career.

 

Would I claim income from stock photography as hobby income on my taxes, since that is what it is to me? Or would the IRS declare this to be a business in spite of how I see it and operate? At least one agency I know of sends contributors with earnings a 1099-MISC every year.

 

Given that a business usually requires the payment of regular income taxes plus self-employment taxes, I want to be sure I don't later have a problem because I didn't file correctly and pay everything required.