Minimise bitmap mini/bmp.bmp #14
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Smashed the 334 bytes original down to a slim 60 bytes, by hand crafting a v1.x BMP file. All versions of the BMP format begin with a basic 14 byte file header. Next is the secondary DIB header; 12 bytes is the smallest possible (IBM OS/2 – v1.x BMP files). Avoiding the more ‘advanced’ / modern bitmap file formats has a big impact for small files, while still widely supported and well documented. Sources: http://www.fileformat.info/format/os2bmp/egff.htm http://www.fileformat.info/format/bmp/egff.htm http://en.wikipedia.org/wiki/BMP_file_format https://msdn.microsoft.com/en-us/library/dd183372(v=vs.85).aspx https://msdn.microsoft.com/en-us/library/dd183374(v=vs.85).aspx
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The committed version is ‘clean’, zero bit padded -totally vanilla. But since each row has to be padded to a 4 byte boundary, we actually have 19 bits of padding (32 bits - 13 bits). Changing ‘bcWidth’ at address 18 from Or, we might choose to hide some other data in those bytes :-) |
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Bump @angea :-) |
Smashed the 334 bytes original down to a slim 60 bytes, by hand crafting a v1.x BMP file.
All versions of the BMP format begin with a basic 14 byte file header.
Next is the secondary DIB header; 12 bytes is the smallest possible (IBM OS/2 – v1.x BMP files).
Avoiding the more ‘advanced’ / modern bitmap file formats has a big impact for small files, while still widely supported and well documented.
Sources:
http://www.fileformat.info/format/os2bmp/egff.htm
http://www.fileformat.info/format/bmp/egff.htm
http://en.wikipedia.org/wiki/BMP_file_format
https://msdn.microsoft.com/en-us/library/dd183372(v=vs.85).aspx
https://msdn.microsoft.com/en-us/library/dd183374(v=vs.85).aspx