Normally, suing a person requires proving their negligence. If Wal*Mart did not breach their duty of ordinary care, then they would not be liable. The owner and driver of the vehicle that hit yours would be the one(s) to sue.
[In accordance with the Avvo community guidelines, this communication does not constitute "legal advice", nor does it form an attorney-client relationship.]
Walmart would likely not be found liable for the damage to your vehicle.
The failure to have a camera running does not make them liable for the damage to your vehicle. When they use camera's it is for their own protection, not necessarily the consumers. Just because you are in the parking lot. The signs about camera's in the parking lot are a deterrent for theft, not vehicle damage.
Second, the type of case you are talking about is a claim for negligence. In order to establish a Negligence claim in Connecticut you have to show that Walmart had a Duty of Care to you, Walmart Breached that duty of care, and Walmarts Breach was the actual and proximate cause of the damages. In your case you will not be able to establish a duty or breach of duty.
You can file suit against the driver of the other vehicle if you have proof that they caused the damage. Your photos do help. Most likely your best course of action is to file a claim with your insurance company for the damages, pay your deductible and let them fight it out if they choose to with the other vehicle owner.