O que é um PNG...

Chunk: Lenght: 4 bytes Chunk Type: 4 bytes Chunk data: 4 bytes (If needed) CRC: 4 bytes ----------------------------- PNG Sig: 89 50 4e 47 0d 0a 1a 0a ----------------------------- IHDR Chunk: Lenght: 00 00 00 0d = 13 bytes Chunk Type: 49 48 44 52 = IHDR Chunk Data: Width: 00 00 00 02 = 2 pixel Height: 00 00 00 02 = 2 pixel Bit depth: 08 = 8 bits per color Colour Type: 02 = Truecolour Compression: 00 = Default Filter: 00 = Default Interlace: 00 = No interlace CRC: fd d4 9a 73 = OK! ----------------------------- IDAT Chunk: Lenght: 00 00 00 19 = 25 bytes Chunk Type: 49 44 41 54 = IDAT Chunk Data: zlib CMF: 08 = CM = deflate, CINFO = 256bytes window size zlib FLG: 1d = FCHECK = 11101 0x081d½31=0 OK!, FDICT = 0, FLEVEL =00 deflate header:01 = BFINAL = 1b last block, BTYPE = 00b no compression deflate lenth: 0e 00 = 00 0e = 14 bytes nlenght: f1 ff = OK! filter: 00 = none line: ff ff ff 00 00 00 = white,black filter: 00 = none line: 00 00 00 ff ff ff = black,white check value: 29 e4 05 fb = OK! CRC: 9b f9 bb 0a = OK! IEND Chunk: Lenght: 00 00 00 00 = No Chunk Data Chunk Type: 49 45 4e 44 = IEND CRC: ae 42 60 82 = OK! ----------------------------- Isso é um PNG sem compressão, a imagem é um quadrado 2x2 com um padrão xadrez.