Backstory: Coordinating a photographer for a small event such as a work function can be a pain. Something similar to how rover and handy work would be a much appreciated time saver.
The Idea: Photographer as a service.
Deep Dive: Similar to other crowdsourced service apps, you would build a platform where users would set a time and budget for an event and a photographer would just show up.
Validation: For less important events (not weddings or graduations) this app could find a niche. To start you could pick a small city and manually coordinate with a few local photographers to prove out the idea before you build it.
Monetization: You would eventually take payments through the app and you could take a cut.