Have just worked through a similar problem with a client. Have a heart-to-heart with him & ask him about getting a pro photographer and get the pic’s taken. Otherwise get him to select appropriate images (you’ll need to steer him to an appropriate source), obviously you’ll need to replace images once you have new originals… your client’s in a visual business - if they he doesn’t want to play ball then you’re in the crap because your site won’t deliver, and it’s your reputation you’re flushing down the toilet. If it’s going that way, then you’re better to agree on price to date, take the money and drop it… You can’t be a professional, and work on amateur terms - and the same goes for him.
That would perhaps be fine if the client had no say in the final product.
It doesnt work this way for our company. The way we present ourselves to the client — we go project by project telling him how solutions we made in the past brought maximum ROI to previous clients, how did it work etc etc (sometimes we can even guarantee certain ROI for the new client or estimate a cost of a lead for him).
Not that client doesnt have a say in final product — he may ask to change this or that in texts, or pictures or make logo bigger if there is a reason to do that, but he doesnt have much overall impact on our marketing and design decisions. Sometimes clients either like what we did anyway or they are simply “afraid” to change something (and for a good reason). We ourselves rarely do just one version of landing page, usually we do few, let it randomly show to customers and tailor those that work best based on results we get.
Lets say client thinks that XYZ should be present on the page and we think that it should be XWASD, we can do 2 pages and show lets say clients version 90% of the time and ours 10% of the time. After a month of usage its quite clear which one is working better.
That’s good. Nothing beats actual evidence of the site in use. 
My sentiments exactly. One of the great things about freelance is that, as a contractor, you can choose your own projects and customers. That’s another instance where an initial questionnaire comes into play. If they don’t answer your questions or give you poor answers, it sends up red flags before you have invested a lot of time and energy into something that’s going nowhere.
You’ll find that the people you want to work with are happy to tell you about their business and plans for their website.
In the design aspect of freelance, if you want to do mock-ups until you are blue in the face, that’s your prerogative. It’s not like that with writing. Once your copy is in their hands, there is nothing to stop them from using it whether or not they decide to pay for it. All though it’s never happened to me, freelance forums are full of laments over non-payment for mockups.