I tend to mix and match these two methods, because you can’t use both in the same place, because you have to have a different CSS sprite for each. And the CSS sprite is the only thing that your CSS code has to change for each change in the background image. As a result, this makes it a bit harder to understand CSS sprites.
Although this is a great way to add a background image, it can also be used to add a custom background to just about everything that your website is using. If you have a background image that you’re using but you want to use it on a background image that is completely different, you can use opacity to add that background image to the background image of your website instead of having to use that image.
Of course, you only need the website to use the background image youve made with opacity. But if you have an image that is used on other pages, you can make it so that that image is visible on the top of the background image on your website.