รวมรูปภาพใน C++

auto pres = System::MakeObject<Presentation>();

pres->get_Slides()->RemoveAt(0);
pres->get_Slides()->AddFromHtml(htmlText1);
pres->get_Slides()->AddFromHtml(htmlText2);

for (int32_t index = 0; index < pres->get_Slides()->get_Count(); index++)
{
    auto slide = pres->get_Slides()->idx_get(index);
    auto fileName = String::Format(u"slide_{0}.png", index);
    slide->GetThumbnail()->Save(fileName, ImageFormat::get_Png());
}