And don't go jumping down any organization's throat about this. The person that you took the picture probably told them it was ok for them to use it and that's good enough for them. Going of at those guys won't do anything good for you. Talk to them, tell them it's your photo and your friend mistakenly gave permission for them to use it. If they like, you could work out a deal to provide something like a one year non exclusive license for their use only. Charge them what they think is fair. I mean, they're using it to promote themselves and to increase their revenue, why should you just get a by line with your name on it. I'm sure they'll be reasonable about compensation. If not, you're not losing anything. Getting a photo credit will do nothing for you 9 times out of 10. As for your friend, just tell them that you gave them the photo for personal use and that you could be making money off of it. I'd go to them after I went to the organization and if you have and agreeable outcome with the deisel folks, you can tell them what happened, what they did wrong, but thank them for putting you in a position to score some cash and that there's no hard feelings as long as they don't do it again. It's not a good reason to ruin a friendship because they didn't realize you were serious about your hobby.