@Kylie56 Good interior photography is difficult to come by and expensive. That's why I've accepted two Instagrammers to stay for free in exchange for good photographs. One came last month, took over my Instagram account, and provided me with amazing shots that I've started incorporating into that listing. Another will come to a separate listing in June.
Because they're on Instagram, I could immediately see their work, which made it easy to decide to say yes. My listings are in Maine, where free Airbnb professional photography is not available.
It sounds as if you want to stay in the Denver area, so my suggestion is that you dig around on Instagram and see if any of the properties has an account, then approach them through that platform. If you have more Instagram followers than they have, it would be an added bonus if you took over their account during your stay. They get great photography and an increase in followers. It's a win-win.
I agree with @Lawrene0 that sending the host a message with dates when you're not going to pay to stay is awkward. But I believe that, rather than entering dates, you can scroll down to "Contact Host" and message them in such a way that it doesn't require them to decline your inquiry.
If you're into Instagram, you could even offer to set up an Instagram account for a property that doesn't already have one. You never know if the host has been considering it or not.