Pour chaque site il y a un bref descriptif de ce qu'on peut y trouver.. J'ai trouve une page avec des sources mais c'est la galere pour la charger This package contains C software to implement JPEG image compression and decompression. C'est sur le JPEG For more information, contact jpeg-info@uunet.uu.net. D'autres liens Sur le GIf This document defines the Graphics Interchange Format(sm). The specification given here defines version 89a, which is an extension of version 87a. The Graphics Interchange Format(sm) as specified here should be considered complete; any deviation from it should be considered invalid, including but not limited to, the use of reserved or undefined fields within control or data blocks, the inclusion of extraneous data within or between blocks, the use of methods or algorithms not specifically listed as part of the format, etc. In general, any and all deviations, extensions or modifications not specified in this document should be considered to be in violation of the format and should be avoided. An Overview of GIF, JPEG and Fractal Compression Techniques Keywords: Image compression, Bandwidth, WWW, GIF, JPEG, Fractal Description tres succinte des formats et quelques mots sur leur principe de fonctionnement.Des adresses en fin de documents. image Compression by Lara MooreJPEG COMPRESSION STEPS ENCODING MODE data converted into frequency space for the discrete cosign transform (DCT) DCT takes an image and divides the image into 8*8 macro blocks colors and pixels are converted into frequency space by describing each block by the number of color shifts (measured by frequency) and the extent of color change (amplitude) Since natural images are normally smooth, the high frequency changes that occur most often with respect to color have a low amplitude (slight shift in color). Therefore the changes in the image itself is minor and yet the amount of data in the can be considerable less LZW and GIF explained----Steve Blackstock C'est vraiment par chance que je veins de tomber dessus. Un lien sur le JPEG (en francais) Assez bien foutu Mise en oeuvre de la méthode JPEG Un autre lien mais ...... Je ne l'ai pas encore essaye Une adresse ou on decrit la structure des fichiers GIF et JPEG File Formats En particulier, comment se decomose un fichier gif Le lien pere est Computer Vision General Information