https://github.com/thoas/picfit https://github.com/thoas/picfit is another golang lib for this, and it's pretty mature at this point. The one thing these don't

https://github.com/thoas/picfit https://github.com/thoas/picfit is another golang lib for this, and it's pretty mature at this point. The one thing these don't support though is smarter cropping that takes into account image contents, which takes enough cpu power to require preprocessing