The frequency components of an image can be displayed after doing a Fourier Transform (FT). An FT looks at the components of an image (edges that are high-frequency, and areas of smooth color as low-frequency), and plots the frequencies that occur as points in spectrum.
In fact, an FT treats patterns of intensity in an image as sine waves with a particular frequency, and you can look at an interesting visualization of these sine wave components on this page (https://plus.maths.org/content/fourier-transforms-images).
In this notebook, we'll first look at a few simple image patterns to build up an idea of what image frequency components look like, and then transform a more complex image to see what it looks like in the frequency domain