Straight from the FAA....
http://www.faa.gov/about/office_org/headquarters_offices/agc/pol_adjudication/agc200/interpretations/data/interps/2015/Williams-AFS-80 - (2015) legal interpretation.pdf
I copied and pasted from the pdf the below, it messed up some words....
Whether an individual taking pictures or videos or gathering other infmmation using a model aircraft under the section 336 carve-out could later sell those pictures, videos, or other information would depend on the person's original intentions in conducting the operation. Ifthe individual's takes the pictures or videos or gathers other information as part of a hobby or recreational activity, then a later decision to sell some or all of those pictures, videos, or other information would not change the character of the operation as part of a hobby or recreational activity that falls within the section 336 carve-out for model aircraft. No FAA authorization for that operation would be required.