How custom resolution supported in .NET WebForms PowerPoint slide to image conversion?

//Opens a PowerPoint presentation
IPresentation presentation = Presentation.Open("../../Data/SlidesSample.pptx");
//Iterates through the slide collection to convert as image
foreach (ISlide slide in presentation.Slides)
{
//Converts the slide as image
Image image = slide.ConvertToImage(Syncfusion.Drawing.ImageType.Bitmap);
//Creates a bitmap of specific width and height
Bitmap bitmap = new Bitmap((int)((image.Width * 500) / 96.0f), (int)((image.Height * 500) / 96.0f), PixelFormat.Format32bppPArgb);
//Sets the resolution
bitmap.SetResolution(500, 500);
//Gets graphics from the custom size bitmap image
Graphics graphics = Graphics.FromImage(bitmap);
//Recreate the image from stream using specified width and height
graphics.DrawImage(image, new Rectangle(0, 0, bitmap.Width, bitmap.Height));
//Saves the image
image.Save("ImageOutput" + Guid.NewGuid().ToString() + ".jpeg");
}
//Closes the presentation
presentation.Close();

'Opens a PowerPoint presentation
Dim presentationDocument As IPresentation = Presentation.Open("../../Data/Test1.pptx")
'Iterates through the slide collection to convert as image
For Each slide As ISlide In presentationDocument.Slides
'Converts the slide as image
Dim image As Image = slide.ConvertToImage(Syncfusion.Drawing.ImageType.Bitmap)
'Creates a bitmap of specific width and height
Dim bitmap As New Bitmap(CInt((image.Width * 500) / 96.0F), CInt((image.Height * 500) / 96.0F), PixelFormat.Format32bppPArgb)
'Sets the resolution
bitmap.SetResolution(500, 500)
'Gets graphics from the custom size bitmap image
Dim gdiGraphics As Graphics = Graphics.FromImage(bitmap)
'Recreate the image from stream using specified width and height
gdiGraphics.DrawImage(image, New Rectangle(0, 0, bitmap.Width, bitmap.Height))
'Saves the image
image.Save("ImageOutput" + Guid.NewGuid().ToString() + ".jpeg")
Next
'Closes the presentation
presentationDocument.Close()