Family Christmas Card

In this example, a business owner in Prague took a picture he found on the internet and used it to advertise his company. This seems quite unnecessary, since it is a supermarket. If it were me, I would have at least google searched a family eating meatballs. However, the business owner did find this picture on Flickr and used it for his own purposes. Even though most of the images that we find on the internet are probably copyright (whether or not they have a watermark), Flickr is a sight where you can find several pictures available for use that are free.
This is technically an issue of copyright, even though at first it may not seem this way. The family posted it most likely with the intentions that it would not appear on a billboard in Prague. This was probably in a place online where understood copyright was in existence.
However, the business man seemed as though he had no intention of actually violating copyright and was extremely apologetic. He offered to apologize, give them free wine, and took it down immediately. I would not take legal action even if it was an infringement. The family and business owner easily settled it.
In an educational setting, if the picture is being used in a way to promote growth and learning, it can be used and would not be a violation of copyright. The teacher could employ fair use and explain her rights easily to the family.