What are some alternatives?
When comparing Imagify.co and Piio, you can also consider the following products
WP Smush - Reduce image file sizes, improve performance and boost your SEO using the free WPMU DEV WordPress...
Crunch Image Optimization - Crunch is an OS X tool for PNG image file optimization.
Gravity Forms - Gravity Forms is one of the best and easiest contact form plugins to create modern forms for websites powered by widely-used WordPress.
imgix - Real-time Image Processing. Resize, crop, and process images on the fly, simply by changing their URLs.
TinyPNG - Make your website faster and save bandwidth. TinyPNG optimizes your PNG images by 50-80% while preserving full transparency!
Cloudinary - Cloudinary is a cloud-based service for hosting videos and images designed specifically with the needs of web and mobile developers in mind.