Hey, great question! Short answer: performance is slightly better with power of 2 textures but other sizes like 720p won’t cause you any real problems for a project like this.
This Stack Exchange thread has some great answers: Why are textures always square powers of two? What if they aren’t? – Game Development Stack Exchange
The power of 2 rule is still great advice and something I think I will stick to it more in the future, but when I was making this course I felt that 512 was not quite enough pixels to work with and 1024 was way too many so I settled for something in between that’s still fairly standard.
