FuzzyOcr failing 'png' tests

[snowcrash+spamassassin <sc...@gmail.com>]

(seems like the 'action' is over here ...)

i'm running SA v3.1.8-r454679, with the FuzzyOCR v3.4.2-release

$SA --lint is error-free.

testing the plugin with provided test messages,

 $SA -t -x < /tmp/ocr-gif.eml
 $SA -t -x < /tmp/ocr-jpg.eml
 $SA -t -x < /dev/FuzzyOcr-3.4.2/samples/animated-gif.eml
 $SA -t -x < /dev/FuzzyOcr-3.4.2/samples/corrupted-gif.eml
 $SA -t -x < /dev/FuzzyOcr-3.4.2/samples/jpeg.eml
 $SA -t -x < /dev/FuzzyOcr-3.4.2/samples/ocr-animated.eml

all show hits/scores with FuzzyOCR rules, as expected.

but,

 $SA -t -x < /tmp/ocr-png.eml
 $SA -t -x < /dev/FuzzyOcr-3.4.2/samples/png.eml

both complete without apparent error, and score numerous other SA-rule hits, but
no FuzzyOCR scores at all.

i have verified that i'm not auto-disabling FuzzyOcr,

  grep focr_autodisable_score FuzzyOcr.cf
    focr_autodisable_score 999

and, since a number of examples seem to be scoring properly, i'm
guessing either FuzzyOcr itself or my config have a problem.

1st question -- can anyone verify success/failure of those png
examples with their own SA+FuzzyOcr setup?

thanks.