At least, how I did it and you might too. And one of the things that anoys me the most is, images loading in an ‘ugly’ way. You’re casually wandering around the internet and you find an interesting website, you visit the website and you see the images loading like this: I don’t know about you, but it kinda triggers me.
Not that hard, just pick an image you like but hold back on uploading the image to WordPress for now.
When that image is loaded, use the SRC of that image to replace the placeholder image with its actual image and lastly remove the lazy class from the image so that it appears.