The FAA uses intent, so if the intent of the flight when you took the photo was as a hobbyist, and then DJI later offers to pay you for the photo, that is okay.
If you were flying with the intent to have DJI (or anyone) pay you for the photo (whether they offered first or ever actually pay for one), then that would be a commercial flight and require a 107 pilot certificate.
If you were flying with the intent to have DJI (or anyone) pay you for the photo (whether they offered first or ever actually pay for one), then that would be a commercial flight and require a 107 pilot certificate.
Hmm, that's a good point,. There is probably some amount of time or income you need to derive to be considered professional, just like the "hobby/loss" rule that the IRS uses to determine if you are really in a business that you are deducting expenses for that has not made money (you can only lose money for so long before the IRS says it's not a real business). Best to check with a financial/accounting type.