That's all there is to it!

Final Thoughts

Of course, there are packages and gems that can do this image transformation outside of a CMS. We've used them before and with great success, but be wary if you're transforming hundreds or thousands of images. The more images and transformations you have to generate the more your server will get bogged down. One strategy is offloading this work to a service like Imgix and Cloudinary that can generate and host these images on the fly. And, seeing the direction the web is going (utilize services, do less stuff on your own) they're both worth checking out.

I hope you found this helpful! Let me know in the comments below if you've use other techniques for responsive background images, or just want to troll.