Compressing files, whether they are an audio, image, or video, is a great method to reduce the amount of a web page’s “weight,” or size of all the on-page content. By reducing file size, you effectively reduce the amount of time it takes to download and render elements, which decreases the page load time and provides a better, more seamless experience for users.
At a high level, data compression is an algorithm that works by rearranging the structure of file to use fewer bits, bytes, etc., of data. You have more than like come across algorithms in your everyday life. Common examples include mpeg, jpeg, and zip, but there are many others. There are a couple of distinct types of compression, lossy and lossless. Depending on the type of file you are working with, one type is typically preferred over another. As an example, lossy compression is typically used for images, audio, and video files because its purpose is to reduce file size by removing unnecessary information. However, a downside, especially for audio files, is a drop in audio quality. On the other hand, lossy compression reduces file size without removing information. A common example of this is the ZIP format.