Retina is a command line tool which performs individual or batch retina to standard resolution image conversion for iOS/Mac app development.
Retina can be used as part of your build toolchain to automatically produce standard resolution versions of retina assets so you don't need to manually produce or maintain a standard resolution set.
To convert all of the @2x retina resolution images in the directory MyProject/images, you can use the following command:
$ retina -S MyProject/images
Or to convert an individual image:
$ retina -S MyProject/images/Default@2x.png
Or to scale up standard resolution assets to retina (for some reason…):
$ retina -R MyProject/images
And to see which images would be converted, but without actually performing any conversion, you can use:
$ retina -S -p MyProject/images
For help and more options, use:
$ retina -h