There is an easy fix for that.
Instead of putting every single piece together, you can just simply use the badge preview, which is at offset 0x1100 and has both the 64x64 (length of 0x2800) and 32x32 (length of 0xA00, comes right after the 64x64 image, might be useless for this) images.
He fixed it already in the rom-properties code, the main reason I suggested this is so it'd be easier to put together badge sets using official data.
@TheMachinumps in case you can't be bothered to build it, I made a release package of the latested master at this time.
https://u.teknik.io/8Kb1p.7z (note that this is an unofficial build and is not a release)