So I have a website and it has a carousel on one of the sidebars. On windows, the pictures that flip through are crisp and clear, but I looked at them on a Mac and they're all fuzzy. Does this have to do with the resolution of a Mac v. the resolution of my Windows laptop, or is it something else?
Your Mac is probably retina, which means it uses twice the amount of pixels to display things.
Some articles with more information:
You can emulate retina displays on Windows in Firefox by changing the pixel ratio. This should replicate the problem you are seeing on the Mac but this time within Windows.