Does your website load quickly, or does it hang before displaying? Slow load time is the fastest way to lose visitors to your site. Big image files could be the problem, but other files can also be slow to load, especially if you use popular toolkits like Bootstrap. There are many ways to reduce file size, but one of the easiest to implement is "compression".
What is compression?
Compression can be lossy or lossless. When you stream a movie on Netflix, you are seeing a compressed file where some of the data is lost. This is lossy compression.Read More.
In lossless compression, nothing is lost. The file is just stored more compactly. For example, you could compress TTTTTuuu as 5T3u. When we compress our web page, we want lossless compression.
How does this work on a web page
When a modern browser requests your web page, it tells the server what kind of compression it can manage, and, if your website is set up for compression, then the server will send a compressed file of the type the browser can understand.. The time to receive and decompress a file is much less than the time to receive an uncompressed file. So your page loads much faster.
Use the Lighthouse Chrome extension and its Performance option to find out if your files are compressed. If they are not, Google will suggest this to you as an "opportunity" to speed up your site.