char strFilename[MAX_PATH];
OPENFILENAME ofn;
ZeroMemory(&ofn, sizeof(ofn));
ofn.lStructSize = sizeof(ofn);
ofn.hwndOwner = hwnd;
ofn.lpstrFilter = "Image Files (*.jpg)\0*.jpg\0";
ofn.lpstrFile = strFilename;
ofn.nMaxFile = MAX_PATH;
ofn.Flags = OFN_EXPLORER | OFN_FILEMUSTEXIST | OFN_HIDEREADONLY;
ofn.lpstrDefExt = "jpg";
if(GetOpenFileName(&ofn))
{
// Do stuff with strFilename here
}