worksheet: add docs for embedded images #174

Job	Run time
Make (gcc)	1m 28s
Make (gcc, USE_STANDARD_TMPFILE=1)	1m 24s
Make (gcc, USE_SYSTEM_MINIZIP=1)	2m 0s
Make (gcc, USE_DTOA_LIBRARY=1)	1m 34s
Make (gcc, USE_NO_MD5=1)	1m 45s
Make (gcc, USE_OPENSSL_MD5=1)	2m 47s
Make (gcc, USE_MEM_FILE=1)	1m 30s
Make (clang)	2m 26s
Make (clang, USE_STANDARD_TMPFILE=1)	2m 9s
Make (clang, USE_SYSTEM_MINIZIP=1)	1m 40s
Make (clang, USE_DTOA_LIBRARY=1)	2m 23s
Make (clang, USE_NO_MD5=1)	1m 59s
Make (clang, USE_OPENSSL_MD5=1)	2m 25s
Make (clang, USE_MEM_FILE=1)	2m 8s
	27m 38s

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