Three 16x16 bilevel fax3 test images covering the key Group 3 variants:
- seq-1c-1b-fax3: basic G3, no fill bits, MSB-first fill order
- seq-1c-1b-fax3-fillbits: G3 with T4Options fill bits (byte-aligned EOLs)
- seq-1c-1b-fax3-lsb: G3 with FillOrder=2 (LSB-first)
All use MinIsWhite photometric with inverted sequential pattern, producing
the same decoded CRC32 hash (71f6a21a) as the uncompressed 1-bit images.
Cross-validated: libtiff writes the images, both libtiff and image-tiff
read them back and agree on the decoded data.
