<%@ import Namespace="System.IO" %>
<%@ import Namespace="System.Drawing.Imaging" %>
<%@ import Namespace="System.Drawing" %>
<%@ import Namespace="System.Drawing.Drawing2D" %>

Function generateThumbnail(ByVal newWidth As Integer, ByVal strFileName As String, ByVal newStrFileName As String)
  Dim bmp As Bitmap
  Dim newHeight As Integer
  Dim resized As Bitmap
  Dim FilePath As String = Server.MapPath("/images/")
 
  bmp = System.Drawing.Image.FromFile(FilePath & strFileName & ".jpg")
  newHeight = (newWidth/bmp.width)*bmp.Height
  resized = new Bitmap(newWidth,newHeight)
  newStrFileName = FilePath & newStrFileName & ".jpg"
 
  Dim g as Graphics = Graphics.FromImage(resized)
  g.SmoothingMode = SmoothingMode.HighQuality
  g.CompositingQuality = CompositingQuality.HighQuality
  g.InterpolationMode = InterpolationMode.High
  g.DrawImage(bmp, new Rectangle(0,0,resized.Width,resized.Height),0,0,bmp.Width,bmp.Height,GraphicsUnit.Pixel)
  g.Dispose()
  resized.Save(newStrFileName,ImageFormat.Jpeg)
  bmp.dispose()
End Function

Function watermark(ByVal strFileName As String, ByVal newStrFileName As String)
  Dim FilePath As String = Server.MapPath("/images/")
  Dim bmp As Bitmap = System.Drawing.Image.FromFile(FilePath & strFileName & ".jpg")
  Dim strWatermark As String = "WATERMARK TEXT"
  Dim canvas As Graphics = Graphics.FromImage(resized)
  Dim StringSizeF As SizeF, DesiredWidth As Single, wmFont As Font, RequiredFontSize As Single, Ratio As Single
  newStrFileName = FilePath & newStrFileName & ".jpg"
  wmFont = New Font("Verdana", 6, FontStyle.Bold)
  DesiredWidth = bmp.Width * .75
  StringSizeF = canvas.MeasureString(strWatermark, wmFont)
  Ratio = StringSizeF.Width / wmFont.SizeInPoints
  RequiredFontSize = DesiredWidth / Ratio
  wmFont = New Font("Verdana", RequiredFontSize, FontStyle.Bold)
  canvas.DrawString(strWatermark, wmFont, New SolidBrush(Color.Beige), 0, 0)
  canvas.DrawString(strWatermark, wmFont, New SolidBrush(Color.FromArgb(128, 0, 0, 0)), 2, 2)
  canvas.DrawString(strWatermark, wmFont, New SolidBrush(Color.FromArgb(128, 255, 255, 255)), 0, 0)
  canvas.DrawString(strWatermark, wmFont, New SolidBrush(Color.FromArgb(128, 0, 0, 0)), 2, 2)
  canvas.DrawString(strWatermark, wmFont, New SolidBrush(Color.FromArgb(128, 255, 255, 255)), 0, 0)
  bmp.SetResolution(96, 96)
  bmp.Save(newStrFileName,ImageFormat.Jpeg)
  canvas.dispose()
  bmp.dispose()
End Function

''resize
''if you wish to have the ".jpg" within the function command, remove it from
''within the function and you can have "resizeme.jpg" and "resized.jpg"
generateThumbnail(100,"resizeme","resized")
 
''watermark
''if you wish to have the ".jpg" within the function command, remove it from
''within the function and you can have "watermarkme.jpg" and "watermarked.jpg"
watermark("watermarkme","watermarked")

Large Image Names:
terry-123WM123.jpg
beachparty-123WM123.jpg
howdy-123WM123.jpg
 
or
 
picture123WM123.jpg
terry123WM123.jpg
 
etc.
 
Now in your web.config file, change your HTTP Handler that you put in there
[
<httpHandlers> 
<add verb="*" path="*.jpg,*.gif" type="ImageHandler,Home" validate="false"/>
</httpHandlers>
]
to
[
<httpHandlers> 
<add verb="*" path="*123WM123.jpg,*123WM123.gif" type="ImageHandler,Home" validate="false"/>
</httpHandlers>
]
 
The star (*) symbolizes that anything with a jpg or gif end tag will be run with the watermark code. Therefore, if you only want specific images to contain the watermark, add a special unique string within the files being called, much like "123WM123". This will call anything that ends with "123WM123.jpg" and "123WM123.gif". Now I suggest doing something more practical like:
*WML.jpg and *WML.gif. WML meaning watermarklarge (for me)