Gambar yang lebih besar berisi potongan ITXt 15204-byte yang berisi beberapa Adobe metadata. Gambar yang lebih kecil juga berisi potongan serupa tetapi lebih kecil, hanya 866 byte. Seperti jawaban Mario, Anda dapat menggunakan pngcrush untuk menghapusnya.
Dapatkan "pngcheck" dan jalankan "pngcheck -v file.png" untuk mencari tahu apa yang ada di file.
File 16.4KB:
$ pngcheck -v 6*
File: 6iutM.png (16643 bytes)
chunk IHDR at offset 0x0000c, length 13
32 x 64 image, 8-bit palette, non-interlaced
chunk pHYs at offset 0x00025, length 9: 2835x2835 pixels/meter (72 dpi)
chunk iTXt at offset 0x0003a, length 15204, keyword: XML:com.adobe.xmp
uncompressed, no language tag
no translated keyword, 15183 bytes of UTF-8 text
chunk cHRM at offset 0x03baa, length 32
White x = 0.31269 y = 0.32899, Red x = 0.63999 y = 0.33001
Green x = 0.3 y = 0.6, Blue x = 0.15 y = 0.05999
chunk PLTE at offset 0x03bd6, length 768: 256 palette entries
chunk tRNS at offset 0x03ee2, length 7: 7 transparency entries
chunk IDAT at offset 0x03ef5, length 506
zlib: deflated, 32K window, maximum compression
chunk IEND at offset 0x040fb, length 0
No errors detected in 6iutM.png (8 chunks, -712.6% compression).
File 1,52KB:
$ pngcheck -v 7*
File: 7W95m.png (1523 bytes)
chunk IHDR at offset 0x0000c, length 13
32 x 64 image, 8-bit palette, non-interlaced
chunk tEXt at offset 0x00025, length 25, keyword: Software
chunk iTXt at offset 0x0004a, length 886, keyword: XML:com.adobe.xmp
uncompressed, no language tag
no translated keyword, 865 bytes of UTF-8 text
chunk PLTE at offset 0x003cc, length 21: 7 palette entries
chunk IDAT at offset 0x003ed, length 498
zlib: deflated, 32K window, maximum compression
chunk IEND at offset 0x005eb, length 0
No errors detected in 7W95m.png (6 chunks, 25.6% compression).