Je recherches le détail (Documentation) de comment décompresser l'image, le format d'encodage du ZIP dans le PNG. Car la doc officielle est plutot succincte sur ce sujet :

13.8 Decompression

The compression technique used in this International Standard does not require the entire compressed datastream to be available before decompression can start. Display can therefore commence before the entire decompressed datastream is available. It is extremely unlikely that any general purpose compression methods in future versions of this International Standard will not have this property.

It is important to emphasize that IDAT chunk boundaries have no semantic significance and can occur at any point in the compressed datastream. There is no required correlation between the structure of the image data (for example, scanline boundaries) and deflate block boundaries or IDAT chunk boundaries. The complete image data is represented by a single zlib datastream that is stored in some number of IDAT chunks; a decoder that assumes any more than this is incorrect. Some encoder implementations may emit datastreams in which some of these structures are indeed related, but decoders cannot rely on this.

En gros débrouille toi !! J'aurais besoin d'une vraie documentation, qui en partant de rien puisse me dire exactement comment décompresser l'image. Faire comme si Zlib n'existait pas.

GT Compressé !!