Hello,
I have a good experience implementing C++ extensions for PHP, I also have a good background in Image Processing based applications.
If I understood correctly you want to write a DLL module that will wrap another existing DLL. Do you have the source code for the original DLL library, the one you intend to make it available to PHP ? I assume your server runs Windows.
We can discuss the details if you are interested to work with me.
Thanks,
Paul