Palette chunk check starts at wrong index

[vHeemstra]

ico-endec-js/src/encoder.js

Line 76 in e8e0ff3

if (imageData[29] !== 'P' && imageData[30] !== 'L' && imageData[31] !== 'T' && imageData[32] !== 'E') {

The indexes for the PLTE-chunk check are wrong. They should be further, depending on the length of the IHDR-chunk + the 4 byte CRC of that chunk (see specification).

In this case, it should skip 4 bytes (CRC of the IHDR-chunk) and another 4 bytes (the size indicator of the PLTE-chunk).

Check out my visual helper for PNG.

[kettek]

Been quite busy, will review and double-check soon