Post-processing the images. An image is just 3 matrices layered on top of each other (red, green and blue) with intensity for each pixel being a value in the matrix.

AI allows professional-grade retouching and image processing to be done by your phone. Making your eyes slightly more pronounced, colourful and sharpened, your lips sharpened but your skin slightly more blurry? Professionals do these tiny things all the time which makes the difference between a normal vacation photo and something you see in in an art museum or used as a movie poster.

AI can do those simple repetitive tasks too quite easily. It makes the difference between a "meh" photo and a "this is awesome" photo. Imagine if your every phone photo went to a professional to do some retouching for 5 minutes, this significantly increases the quality of your photos.