Believe it or not, the brokest people really have the least to worry about in these cases. I keep hearing from people how broke they are and how they can't pay. Well, that actually works to your benefit if it is the truth. If I was broke, I would simply tell them that. You can go spend thousands of dollars to come after me but if my monthly checking account hovers around $200 per month, there is not much to get.
Exactly. There is such a thing as "judgment proof." And although I don't advocate it as your sole defense, I believe it strikes terror into the heart of prosecuting attorneys.
Basically, if you work freelance, there is no paycheck to garnish. If you are retired or collecting social security garnishment is not possible. Keep in mind that if you do get a job over the next 7 years, they would be able to garnish your paycheck (up to 25%). And also not paying this debt will ding your credit.
On the flip side, will your adversary want to waste time going to court, risk loosing, be forced to produce a bunch of contracts and documents, all for a judgment that will go unpaid?
This may not make them walk away. But I think any reasonable offer you make has to be presented to their client. So without admitting guilt, in the interest of ending this amicably, make a low-ball offer*. Tell the attorney that when he presents your offer to his client to be sure to mention that you are pretty much judgment proof and broke and you will be putting this payment on your credit card or selling your bicycle to pay for it.
*BTW, what "low-ball" is depends on the stock agency involved, the registration status of the image, the current and previous license price, comparable image prices, and the prevalence of the image all over the Internet. In most cases I'm thinking $10 to $200, probably $50 most of the time.)