What are some alternatives?
When comparing Ameto.de and WP Smush, you can also consider the following products
Imagify.co - Resize, Crop and Manipulate your images on the fly!
ImageOptim - Faster web pages and apps.
Kraken - Kraken is a robust, ultra-fast image optimizer. Thanks to its vast array of optimization algorithms Kraken is a world ahead of other tools. Want to save bandwidth and improve your website's load times? Look no further and welcome to Kraken!
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.
Yoast Plugins - Yoast offers plugins to improve SEO and optimize web sites and blogs.