ResizePixel - Free image editor to crop, resize, flip, rotate and convert images online
imgix - Real-time Image Processing. Resize, crop, and process images on the fly, simply by changing their URLs.
Bulk Resize Photos - Resize large photos in bulk
Cloudimage - Cloudimage.io is the easiest way to resize, store, and deliver your images to your customers through a rocket fast CDN.
Dribbble Resizer - Resize your designs for sharing on Dribbble
Sirv - Dynamic image processing, hosting and rich-media for retailers and eCommerce.