What photos do
Homeowners hire from pictures. A driveway before and after does more than any paragraph you could write about the same job, and it does it in the two seconds somebody spends deciding whether to keep reading.
They also prove you were there. A photo of a job in the town the page is about is the kind of local detail that makes a town page a real page rather than a template, which is the part that matters to Google, through the writing around it.
Where they hurt
A photo straight off a phone can be several megabytes. Put eight of those on a page and it takes long enough on a truck's signal that most people leave. That's a real cost and it happens before anybody sees the work.
The fix is boring: save them at the size they'll be shown at, in a modern format, and let the ones further down the page load only when somebody scrolls to them. Any decent site does this without being asked.
Naming them, and the text underneath
Give each photo a plain file name and a short description of what's in it, for the people who browse with a screen reader and for the machines that can't see the picture. Write what it shows, in a few words, the way you'd describe it on the phone.
Don't stuff those descriptions with job names and towns. It reads as spam to anything checking, and it does nothing for the person it was built for.
The photos on your listing
Google recommends adding photos to your Business Profile, and it's worth doing, but treat it as something a customer sees rather than as a lever. What's been tested about photo volume puts it far down the list of things that move the map.
Post a few real ones every so often, of finished work, in the towns you serve. It keeps the listing looking like a business somebody runs, and that's the point of it.