The next generation of zimg which is written in golang.
lThe main features of zimg v4 include:

• Easy build with less 3rd library
• RESTful api
• The most wanted feature: authentication
• Maximum compatibility with older version of zimg
• Full features of older version of zimg
• Auto rotation of pictures
• Support progressive JPEG
• GIF image optimization
• User-defined-url [maybe]
• Our new object-storage-system [maybe]