Is My Pet Sitter Guilty Of Fraud?

Context: I hired a cat sitter a while ago. All I asked is that once a day, the sitter swung by the house to make sure she got food/water, took care of the litter box, and sent us a photo to show us that she she's okay. The sitter did a great job, and i got a photo every day.

I'm out of town this week, so I hired the sitter again. This time however, I noticed that the photos on some of the days looked 100% identical to photos of the cat that the sitter had sent when she was previously watching our cat.

Sure enough, the metadata confirmed that the photos I had suspicions about were screenshots, and our alarm system app confirmed that the doors to our house were never opened on those days.

I'm not going to confront the sitter until I get back and they no longer have my house key. But am I right that this seems like a pretty clear cut case of fraud? And if so, do I have options that I could pursue besides of course, not paying the sitter for the days they didn't show up?

The sitter is a law school student too, for what it's worth.