If I'm reading this correctly, you're essentially asking if there is a market for marketing services.

To which the answer is a resounding 'yes'. Effective marketing and sales is essentially giving people money.

If you are wondering whether photography and facebook content is effective, there are plenty of people who use this alone, or to augment other efforts. Success is more dependent on the ability than the channel selected, in my humble opinion.

The easiest way to get started with something like this if you aren't 100% positive on your ability to deliver is to do it for free. The only risk is your own time.

This also gives you an opportunity to base your price off of value. Many people start out arbitrarily determining their worth and start charging per hour. With this, you might discover 5 hours of work yields $5000 in revenue for a client, which you could easily charge $1000 for.

You just started making $200 an hour.

If you choose to go this route, I would be careful with choosing your first test client. Some types of businesses (fashion retail for instance) are heavily influenced by photography while others (industrial chemical manufacturing) are not. If you choose a category without a lot of leverage you will have skewed results on the value your talents can produce.