baseDir is [tools/tests/skdiff/baseDir/]
comparisonDir is [tools/tests/skdiff/comparisonDir/]
not writing any diffs to outputDir [tools/tests/skdiff/identical-bits-or-pixels/output-actual/]
compared 3 file pairs:
 2 file pairs contain exactly the same bits
 1 file pairs contain the same pixel values, but not the same bits