csoellinger / php-class-png-chunks Goto Github PK

Thanks for the class. Trying to use it to read/write new tEXt chunks. Reading and removing chunks works fine. But after applying addChunk to assets/test.png it causes a CRC error:

trying: $png->addChunk('tEXt', 'Comment', 'Foobar');

leads to error:

incorrect crc for Foob chunk (is 6e74b19e, should be 026cafc9)

Invalid chunk type found at file position 30503. This may indicate garbage at the end of the file.

(error message by freeware tool TweakPNG http://entropymine.com/jason/tweakpng/)

I also tried $png->addChunk('tEXt', 'Comment_3', 'Foobar'); but leads to same message (different CRCs and position).

Any idea what is goind wrong? Thanks in advance!