Hi, I haven't worked on this for years! I've released the code for this tiny project with absolutely no strings attached, however, so it can be used even without attribution.
Its ABK code was included in jAMOS. I also did a version in C++ for AROS and MorphOS, which was less stable.
My most recent related project was XAMOS (which included some ABK code from the AROS/MorphOS C++ version, but made cross-platform) and that is no longer active either.
In reply to Bippy's post from July 2013, the code simply plots the sprites into 24 bit so respecting the native colour palettes to save to paletted PNG is not possible without a rewrite. Similarly, editing sprites and saving back to ABK isn't really possible with this code base.
AMOS ABK sprite bank format is quite simple and well documented though, the appendix to the AMOSPro manual describes it (which is what the code for this viewer was based on).