Force use of ImageMagick image library

Forces WordPress to use the ImageMagick image library. This plugin only instructs WordPress to use the ImageMagick library. It doesn’t change how (or when) WordPress generates images, and it doesn’t provide any additional functionality for creating or resizing images.

If you need to know more about ImageMagick, then visit the official website. Full information about Post Thumbnails and image size and quality are in the WordPress Codex.