It does. I have a native convert.exe. But emacs (on Unix and Cygwin) now has builtin ImageMagick support (as in emacs can resize images without calling an external program). The precompiled Windows binaries don't have it builtin though and according to Glenn Morris answer it is simply not available for Windows and NextStep.
Hence I am searching for a solution to emulate the builtin support in a way such that other people's emacs lisp code doesn't have to be aware of it. From org-mode I can remember, that they query for some `imagemagick-*` function or variable that is not defined in the Windows binaries.