imgix - Real-time Image Processing. Resize, crop, and process images on the fly, simply by changing their URLs.
CarrierWave - Solution for file uploads for Rails, Sinatra and other Ruby web frameworks.
Cloudimage - Cloudimage.io is the easiest way to resize, store, and deliver your images to your customers through a rocket fast CDN.
Uppy - The next open source file uploader for web browsers
Sirv - Dynamic image processing, hosting and rich-media for retailers and eCommerce.
tus.io - File Uploads