I have had the exact same question. I work primarily with franchise companies that have multiple locations that offer the same services, so this question has been on my mind for a while.

I currently use the same photos for the most part on each of the franchise location's G+ listings, Yelp, CitySearch, etc., without changing the image file names. I have been doing it this way for years and haven't ever seen a negative impact, but would be curious to know if there is potential upside to using unique file names for each image in each location.

Would love to hear what others' opinions are on this topic.

I have read a lot about how it is important to keep URLs as short as possible, but I have also seen first-hand how longer, descriptive URLs have performed really well.

You'll probably get different answers from different people, and I don't know that either is right or wrong. In my opinion the longer URL would be more beneficial, assuming that trail of URLs isn't going to continue on and get too long - /anniversary_flowers/dozen_roses/red/bouquet - you get the idea.

My reasoning behind going with the longer URL structure is because you get the benefit of having both potential keyword search terms, anniversary flowers & dozen roses, in the page URL. Hope that helps!