Change DPI and/or Graphic File Dimensions Using ASP.NET and VB.NET

• Changed the objOptImage object from Image to Bitmap so I could change the resolution
• Added code to ensure the longest side was 600px and the smaller side was adjusted appropriately
• Removed the Format16bppRgb555 when creating a new Bitmap

Imports System.IO
Imports System.Drawing

Partial Class Graphic
	Inherits System.Web.UI.Page

	Protected Sub Resize(ByVal sender As Object, ByVal e As EventArgs)

		' GET THE UPLOADED FILE.
		Dim hfc As HttpFileCollection = Request.Files

		If hfc.Count > 0 Then

			Dim hpf As HttpPostedFile = hfc(0)

			If hpf.ContentLength > 0 Then

				Dim sImageName As String = hpf.FileName

				' FIRST SAVE THE FILE ON THE SERVER.
				hpf.SaveAs(Server.MapPath("~/" & Path.GetFileName(sImageName)))

				' ORIGINAL WIDTH AND HEIGHT.
				Dim bitmap As New Bitmap(Server.MapPath("~/" & Path.GetFileName(hpf.FileName)))

				Dim iwidth As Integer = bitmap.Width
				Dim iheight As Integer = bitmap.Height

				bitmap.Dispose()

				' SHOW DETAILS OF ORIGINAL IMAGE WITH SIZE.
				Info.InnerHtml = "<b>Original Image</b> "
				Info.InnerHtml = Info.InnerHtml & "<br /> Width: " & iwidth & ", Height: " & iheight & "<br /> " &
					Double.Parse(hpf.ContentLength / 1024).ToString("N0") & " KB <br>"

				' ONCE WE GOT ALL THE INFORMATION, WE'll NOW PROCESS IT.

				' CREATE AN IMAGE OBJECT USING ORIGINAL WIDTH AND HEIGHT.
				' ALSO DEFINE A PIXEL FORMAT (FOR RICH RGB COLOR).

				Dim intSavedHeight As Int32 = iheight
				Dim intSavedWidth As Int32 = iwidth

				If iwidth > iheight Then
					iwidth = 600
					iheight = Convert.ToSingle((iwidth / intSavedWidth) * iheight)
				Else
					iheight = 600
					iwidth = Convert.ToSingle((iheight / intSavedHeight) * iwidth)
				End If

				Dim objOptImage As Bitmap =
					New Bitmap(iwidth, iheight)
				objOptImage.SetResolution(72, 72)

				' GET THE ORIGINAL IMAGE.
				Using objImg As Image =
					Image.FromFile(Server.MapPath("~/" & sImageName))

					' RE-DRAW THE IMAGE USING THE NEWLY OBTAINED PIXEL FORMAT.
					Using oGraphic As Graphics =
							Graphics.FromImage(objOptImage)

						With oGraphic

							Dim oRectangle As New Rectangle(0, 0, iwidth, iheight)

							.DrawImage(objImg, oRectangle)
						End With

					End Using

					' SAVE THE OPTIMIZED IMAGE.
					objOptImage.Save(HttpContext.Current.Server.MapPath("~/Images/" & sImageName),
						Imaging.ImageFormat.Jpeg)

					objImg.Dispose()
				End Using

				objOptImage.Dispose()

				' FINALLY SHOW THE OPTIMIZED IMAGE DETAILS WITH SIZE.
				Dim bitmap_Opt As New Bitmap(Server.MapPath("~/images/" & Path.GetFileName(sImageName)))

				Dim iwidth_Opt As Integer = bitmap_Opt.Width
				Dim iheight_Opt As Integer = bitmap_Opt.Height

				bitmap_Opt.Dispose()

				' FOR SIZE.
				Dim OptImgInfo As New FileInfo(Server.MapPath("~/images/" & Path.GetFileName(sImageName)))
				Dim ifileSize As Integer = OptImgInfo.Length    ' GET THE SIZE IN BYTES.

				Info.InnerHtml = Info.InnerHtml & "<br / ><b>Optimized Image</b>"
				Info.InnerHtml = Info.InnerHtml & "<br /> Width: " & iwidth_Opt & ", Height: " & iheight_Opt
				Info.InnerHtml = Info.InnerHtml & "<br /><span style=color:green>" &
					Double.Parse(ifileSize / 1024).ToString("N0") & " KB</span>"
			End If

		End If

	End Sub

End Class

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