pngtopnm: reading a 640w x 300h image, 8 bits
pngtopnm: truecolor+alpha, not interlaced, base filter
pngtopnm: background {index, gray, red, green, blue} = {0, 0, 0, 0, 0}
pngtopnm: tRNS chunk (transparency): not present
pngtopnm: gAMA chunk (image gamma): not present
pngtopnm: sBIT chunk: present
pngtopnm: cHRM chunk: not present
pngtopnm: PLTE chunk: not present
pngtopnm: bKGD chunk: not present
pngtopnm: hIST chunk: not present
pngtopnm: pHYs chunk: present
pngtopnm: oFFs chunk: not present
pngtopnm: tIME chunk: not present
pngtopnm: pCAL chunk: not present
pngtopnm: sRGB chunk: not present
pngtopnm: writing a PPM file (maxval=255)
pnmremap: 16 colors found in colormap
pnmremap: 0 pixels not matched in color map
192000 pixels, 77753 bytes, (19.01% compression)
#081020=0
#08182d=1
#0c2445=2
#183559=3
#204971=4
#315d86=5
#41759a=6
#ffffff=7
#518eb2=8
#82868e=9
#65a2c2=10
#969a9e=11
#7dbad7=12
#aeb2b6=13
#9acae3=14
#c2e3ef=15
pnmtopng: reading a PPM file (maxval=255)
pnmtopng: Finding colors in input image...
pnmtopng: 16 colors found
pnmtopng: reading ordered palette (colormap)...
pnmtopng: 16 colors found
pnmtopng: PNG palette has 16 entries, 0 of them non-opaque
pnmtopng: Writing 4-bit color indexes
pnmtopng: writing a 4-bit palette file