Image compression

thumb|Continuously varied JPEG compression (between Q=100 and Q=1) for an abdominal [[CT scan]]

Portable Network Graphics (PNG, officially pronounced , colloquially pronounced ) is a raster-graphics file format that supports lossless data compression. PNG was developed as an improved, non-patented replacement for Graphics Interchange Format (GIF).

WebP ( ) is a raster graphics file format developed by Google and intended as a replacement for the JPEG, PNG, and GIF file formats on the web. It supports image compression (both lossy and lossless), as well as animation and alpha compositing. The sister project for video is called WebM.

technique representing data as sums of cosine functions

reduction of image size to save storage and transmission costs

image compression standard and coding system

compressed image file format

open-source raster-graphics file format

metric used to measure picture quality

method of digital image compression using fractals

mathematical technique used in data compression and analysis

encoding images using a lower resolution for chroma channels

image file format

JBIG is an early lossless image compression standard from the Joint Bi-level Image Experts Group, standardized as ISO/IEC standard 11544 and as ITU-T recommendation T.82 in March 1993. It is widely implemented in fax machines. Now that the newer bi-level image compression standard JBIG2 has been released, JBIG is also known as JBIG1. JBIG was designed for compression of binary images, particularly for faxes, but can also be used on other images. In most situations JBIG offers between a 20% and 50% increase in compression efficiency over Fax Group 4 compression, and in some situations, it offer

lossless and near-lossless compression of continuous-tone still images

digital image file format

interlacing algorithm for raster images

raster graphics format

The macroblock is a processing unit in image and video compression formats based on linear block transforms, typically the discrete cosine transform (DCT). A macroblock typically consists of 16×16 samples, and is further subdivided into transform blocks, and may be further subdivided into prediction blocks. Formats which are based on macroblocks include JPEG, where they are called MCU blocks, H.261, MPEG-1 Part 2, H.262/MPEG-2 Part 2, H.263, MPEG-4 Part 2, and H.264/MPEG-4 AVC. In H.265/HEVC, the macroblock as a basic processing unit has been replaced by the coding tree unit.

JBIG2 is an image compression standard for bi-level images, developed by the Joint Bi-level Image Experts Group. It is suitable for both lossless and lossy compression. According to a press release from the Group, in its lossless mode JBIG2 typically generates files 3–5 times smaller than Fax Group 4 and 2–4 times smaller than JBIG, the previous bi-level compression standard released by the Group. JBIG2 was published in 2000 as the international standard ITU T.88, and in 2001 as ISO/IEC 14492.

file format

lossless bitmap image file format