Need Advice: I'm Stuck on a Distribution Problem

I'm looking for some architectural and product advice before I spend time building a prototype.

Here's the situation:

After weddings, birthdays, school events, etc., photographers usually hand over thousands of photos on a USB drive. The client plugs it into their laptop and simply opens the photos using the default photo viewer.

I had an idea for a photo viewer that uses the laptop's webcam to recognize the people sitting in front of the screen. During a slideshow, it would automatically spend more time on photos containing those viewers and quickly skip photos that don't.

The implementation seems possible. The problem I'm stuck on is distribution and adoption.

I don't think most people would:

• Install a dedicated application just to view one event's photos.
• Upload thousands of offline photos to a website just for this feature.

The natural workflow today is simply:

Photographer → USB drive → Open photos using the default photo viewer.

That's where I'm stuck.

My questions

• Is there any practical way to integrate with existing photo viewers on Windows or macOS?
• Do the default photo viewers support plugins or extensions for something like this?
• Is there a distribution model I'm overlooking?
• If you were building this, how would you make it fit naturally into the existing workflow without requiring users to install another application?
• Have you faced a similar situation where the product idea seemed feasible, but distribution was the real challenge?

I'm genuinely looking for suggestions from developers who have dealt with similar problems. Any ideas or alternative approaches would be greatly appreciated.