For create the 16 and 32 bits DLL of Zlib 1.20 For the 16 bits : unzip zlib120.zip and copy file from contrib\vstudio\vc15_16 and from contrib\minizip in the same directory open zlib16.mak with Microsoft Visual C++ 1.52 For the 32 bits : unzip zlib120.zip and copy file from contrib\vstudio\vc70_32 and from contrib\minizip in the same directory You can also need unzip http://www.winimage.com/zLibDll/crtdll.zip If you are using x86, use target Release open zlibvc.sln with Microsoft Visual C++ 7.0 (Visual Studio .net) Note : You don't need recompile yourself. There is compiled .LIB in http://www.winimage.com/zLibDll . See this page for more information Gilles Vollant info@winimage.com