$> binwalk moon.png

DECIMAL       HEXADECIMAL     DESCRIPTION
--------------------------------------------------------------------------------
0             0x0             PNG image, 600 x 593, 8-bit/color RGB, non-interlaced
290           0x122           Unix path: /www.w3.org/1999/02/22-rdf-syntax-ns#"> <rdf:Description rdf:about="" xmlns:xmpMM="http://ns.adobe.com/xap/1.0/mm/" xmlns:stRef=
944           0x3B0           Zlib compressed data, best compression
411781        0x64885         Zip archive data, encrypted at least v1.0 to extract, compressed size: 35, uncompressed size: 23, name: flag.txt
411976        0x64948         End of Zip archive