C# - Out Of Memory Exception While Writing 300dpi Images

I have a requirement that to create a image with 300DPI, but during the composition of image, like addding the resources (font, images) I am getting out of memory exception.

using (Bitmap pg = new Bitmap(GetPixelsFromInches(float.Parse(pageWidth), dpi, actualDpi), GetPixelsFromInches(float.Parse(pageHeight), dpi, actualDpi)))
{
pg.SetResolution(float.Parse(dpi), float.Parse(dpi));
Graphics gr = Graphics.FromImage(pg);
gr.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
System.Drawing.Rectangle pgRect = new System.Drawing.Rectangle(0, 0, pg.Width, pg.Height);
SolidBrush solidWhite = new SolidBrush(Color.White);
gr.FillRectangle(solidWhite, pgRect);
currentPageDisplayed = xNode.Attributes["id"].Value;
foreach (XmlElement xElement in xNode)
{
//Here I am writing each elements, like texts or images.
DrawImageForElements(xElement, , dpi, actualDpi);
}
MemoryStream myMemoryStream = new MemoryStream();
//pg.Save(myMemoryStream, System.Drawing.Imaging.ImageFormat.Bmp);
String filename=@"c:images" + currentPageDisplayed + "+.png";
pg.Save(filename, System.Drawing.Imaging.ImageFormat.Png);
myMemoryStream.Dispose();
gr.Dispose();
pg.Dispose();
}