Cloudinary is nice, but it gets expensive really fast on a high traffic site that's image heavy and bandwidth optimized. For example, a single image might have 5-6 versions on top of the original -- low quality thumbnail, high quality thumbnail, default, default 2x retina, default 3x retina. Then activate their webp service and perhaps offer another image aspect ratio. Each is a conversion that counts against your quota. Now you've got 15+ (con)versions and you're shelling out hundreds of dollars a month.