Can't read specific png file

[Benny-]

This image can't be read by puzzle-diff.

puzzle-diff ./twiley.png ./twiley.png 
# outputs -> Unable to read [./twiley.png]

[Benny-]

The following error occurs if the image is read using the library api (using puzzle.get_cvec_from_file("twiley.png")):

*BUG* File: [vector_ops.c] Line: [18]

[Benny-]

Here is another file. It is a small file compared to the previous one. This one core dumped:

puzzle-diff ./rforgallopfrey.png  ./rforgallopfrey.png 
# Outputs: *BUG* File: [dvec.c] Line: [336]
#          Aborted (core dumped)

The error it produces is different, so it might have a different cause.