Do you think the photo revenue will be stable in the long term? I don't really know much about the stock photo market, but if you spent a few years to get 10x the amount of photos there as you have now, could you be making $5000 / month off of just that?
It is long term income. I know personally a few guys that are making thousands of dollars from same amount of photos I have (but they are much more talented than I am).
