Performance

jimp v0.2.19 - Image processing in pure JavaScript. Bilinear interpolation only.
lwip v0.0.8 - Wrapper around CImg, compiles dependencies from source.
imagemagick-native @5ab570e - Wrapper around libmagick++, supports Buffers only.
imagemagick v0.1.3 - Supports filesystem only and "has been unmaintained for a long time".
gm v1.21.0 - Fully featured wrapper around GraphicsMagick's gm command line utility.
sharp v0.12.0 / libvips v8.1.1 - Caching within libvips disabled to ensure a fair comparison.

Decompress a 2725x2225 JPEG image, resize to 720x480 using bicubic interpolation (where available), then compress to JPEG.

Module	Input	Output	Ops/sec	Speed-up
jimp	file	file	0.99	1.0
jimp	buffer	buffer	1.05	1.1
lwip	file	file	1.13	1.1
lwip	buffer	buffer	1.13	1.1
imagemagick-native	buffer	buffer	1.67	1.7
imagemagick	file	file	5.19	5.2
gm	buffer	buffer	5.56	5.6
gm	file	file	5.59	5.6
sharp	stream	stream	21.91	22.1
sharp	file	file	22.79	23.0
sharp	file	buffer	22.91	23.1
sharp	buffer	file	23.03	23.3
sharp	buffer	buffer	23.15	23.4

Greater performance can be expected with caching enabled (default) and using 8+ core machines.

The I/O limits of the relevant (de)compression library will generally determine maximum throughput.

Requires both ImageMagick and GraphicsMagick:

brew install imagemagick
brew install graphicsmagick

sudo apt-get install imagemagick libmagick++-dev graphicsmagick

sudo yum install ImageMagick-devel ImageMagick-c++-devel GraphicsMagick

git clone https://github.com/lovell/sharp.git
cd sharp
npm install
cd test/bench
npm install
npm test