Manipulate images with minimal use of memory via ImageMagick

This pure Ruby library can read and write PNG images without depending on an external image library, like RMagick. It tries to be memory efficient and reasonably fast. It supports reading and writing all PNG variants that are defined in the specification, with one limitation: only 8-bit color depth is supported. It supports all transparency, interlacing and filtering options the PNG specifications allows. It can also read and write textual metadata from PNG files. Low-level read/write access to PNG chunks is also possible. This library supports simple drawing on the image canvas and simple operations like alpha composition and cropping. Finally, it can import from and export to RMagick for interoperability. Also, have a look at OilyPNG at https://github.com/wvanbergen/oily_png. OilyPNG is a drop in mixin module that implements some of the ChunkyPNG algorithms in C, which provides a massive speed boost to encoding and decoding.

ruby-vips is a binding for the libvips image processing library. It is fast and it can process large images without loading the whole image in memory.

RMagick is an interface between Ruby and ImageMagick.

Ruby/Pango is a Ruby binding of pango-1.x based on GObject-Introspection.

paperclip-optimizer is a Paperclip processor for optimizing and minifying uploaded images.

Ruby bindings for cairo

A ruby ImageMagick/GraphicsMagick library that doesn't suck

Thin ImageMagick DSL with smart command composition

ImageScience is a clean and happy Ruby library that generates thumbnails -- and kicks the living crap out of RMagick. Oh, and it doesn't leak memory like a sieve. :) For more information including build steps, see http://seattlerb.rubyforge.org/

Ruby/RSVG2 is a Ruby binding of librsvg-2.x.

RMagick replacement which uses ImageMagick directly by constructing chainable commands

Simple Ruby stateless module interface to imagemagick.

Simple image manipulation using Apple's Core Image technology. Scale, rotate, flip, convert, overlay, and more.

dHash and IDHash perceptual image hashing/fingerprinting

Turns a video file into an animated gif.

A service for image manipulation - built as an extensible wrapper of Imagemagick which handles caching, c/o the Dragonfly gem.

Ruby bindings for DevIL cross platform image loading library

a library for automated lossless image optimization