The amount of compression can be adjusted to achieve the desired trade-off between file size and visual quality.

From version 6b of libjpeg of 27 March 1998, Miyasaka Masaru forked a branch named libjpeg/SIMD, which included x86 SIMD optimisations.

For this version Josh Aas from Mozilla Research reworked the Perl script jpegcrush from x264's main developer Loren Merritt and integrated it into the code base of libjpeg-turbo.

[11] On 10 July 2014, Mozilla released version 2.0, which mainly added trellis quantisation and is now able to reduce the size of baseline JPEGs also.

[17] In version 7, support for arithmetic coding was introduced, which earlier has been rejected because of the patent situation, as well as the crop feature in jpegtran (-crop).

[26] libjpeg-turbo is a fork of libjpeg that uses SIMD instructions to accelerate baseline JPEG encoding and decoding.

Many projects are now using libjpeg-turbo instead of libjpeg, including popular Linux distributions (Fedora, Debian, Mageia, openSUSE, ...), Mozilla, and Chrome.

[28][29][30] Apart from performance, some projects have chosen to use libjpeg-turbo because it allows them to retain backward ABI compatibility with the older libjpeg v6b release.

[32] libjpeg-turbo chooses not to support SmartScale, because it is not an ITU-T standard and because their own research finds it (and DCT scaling) ineffective.

To achieve this, it uses more processing power for the encoding (asymmetry) while retaining full compatibility with the JPEG standard and requiring no changes on the decoder side.

The techniques MozJPEG uses to achieve high compression include optimising Huffman trees, using progressive coding to optimally split the spectrum of DCT coefficients into separate scans, and through the use of trellis quantisation.