The JPEG image compression technique consists of 5 functional stages. Below are explain how it does work and where it is supported.
The JPEG image compression technique consists of 5 functional stages.
1. an RGB to YCC color space conversion,
2. a spatial subsampling of the chrominance channels in YCC space
3. the transformation of a blocked representation of the YCC spatial
image data to a frequency domain representation using the
discrete cosine transform,
4. a quantization of the blocked frequency domain data according to
a user-defined quality factor, and finally
5. the coding of the frequency domain data, for storage, using
The human visual system relies more on spatial content and acuity thanit does on color for interpretation. For this reason, a color photograph,represented by a red, green, and blue image, is transformed to differentcolor space that attempts to isolate these two components of imagecontent; namely the YCC or luminance/chrominance-red/chrominancebluecolor space. This color space transformation is performed on apixel-by-pixel basis with the digital counts being converted according tothe following rulesGPEG compression stap: jpeg compressed image data > decoding > de-quantization > inverse DCT > up-sampling > color transform> raw image data > color transform > downsampling > forward DCT > quantization > en coding.
PNG COMPRESSIONPNG full form name:[ protable network graphics ]How does it work? When you upload a PNG (Portable Network Graphics) file, similar colors in your image are combined. This technique is called “quantization”. By reducing the number of colors, 24-bit PNG files can be converted to much smaller 8-bit indexed color images. All unnecessary metadata is stripped too. The result: better PNG files with 100% support for transparency. Is it supported everywhere?The files produced by TinyPNG are displayed perfectly on all modern browsers including mobile devices. Still need to support Internet Explorer 6? It normally ignores PNG transparency and displays a solid background color. With TinyPNG the background becomes transparent again. Binary transparency without any workarounds!
The TIFF image format is generally regarded as the gold standard for long-term storage of static image data. It is flexible, widely supported, and rich in its treatment of both image data and metadata. Its historical disadvantage has been its large file sizes; this can, however, be mitigated by the use of compression, support for which is built into the format and described in the TIFF compression tag for each file.