All prebuilt libraries are available in the php-libs repositories
The filename format is:
libjpeg-x.y.z-vcversion.zip
where x.y.z defines the version, vcversion which Visual C++ has been used.
Only static library (.lib) are available for now.
To compile libjpeg to be used with PHP (and more generally with any decent VC), the makefile has to be altered, add the /MT flag as follow (~ line 15):
CFLAGS= $(cflags) $(cdebug) $(cvars) -I. /MD
then
copy jconfig.vc jconfig.h
Two modes are available, debug or non debug (fully optimized).
nmake /f makefile.vc nodebug=1
nmake /f makefile.vc
For VC11 you might need to copy the win32.mak from the Windows SDK file into the jpeg source dir.