AI Generated Images in Lessons

I have recently started using Bing's AI Image Creation tool for generating illustrations in lesson that I create for compliance training at the university that I work at.  (Previously I have created original illustrations and photos, but the quality of my illustrations are often not at the level of what I can prompt with the AI tool.)

What are people's thoughts about the use of the AI image use?

If you are using AI images how are you crediting them in the lessons?  

Is there a concern, since so many of these AI images are derived from existing illustrations and photos that are created by artists and published to the internet?