i can't delete image file...

hi all,

i'm using a page called ShowImage.aspx in my project. The page's doing a crop for each picture and shrink them.

when i show a picture in my another pages as above way, i can't delete them.
File.Delete(Server.MapPath("path")) is not work.
Error Message : ..... the file is using another project.....

for example, i call a pictue as this way :
<img src='ShowImage.aspx?src=path&width=50&height=50&comp=80(0-100)'>

i'm writing below my ShowImage.aspx page's content.

already now thanks...

Imports System.Drawing.Imaging
Imports System.Drawing
Imports System.Drawing.Drawing2D
Public Class ShowImage
    Inherits System.Web.UI.Page

#Region " Web Form Designer Generated Code "

    'This call is required by the Web Form Designer.
    <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()

    End Sub

    'NOTE: The following placeholder declaration is required by the Web Form Designer.
    'Do not delete or move it.
    Private designerPlaceholderDeclaration As System.Object

    Private Sub Page_Init(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Init
        'CODEGEN: This method call is required by the Web Form Designer
        'Do not modify it using the code editor.
        InitializeComponent()
    End Sub

#End Region

    Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Dim strFilename As String
        Dim i As System.Drawing.Image
        strFilename = Server.MapPath(Request.QueryString("src"))
        i = System.Drawing.Image.FromFile(strFilename)
        Dim Thumbnail As New System.drawing.Bitmap(Request.QueryString("width"), Request.QueryString("height"), PixelFormat.Format24bppRgb)
        Dim g As Graphics = Graphics.FromImage(Thumbnail)
        If (i.Width / i.Height) < (Request.QueryString("width") / Request.QueryString("height")) Then
            ' portrait image processing
            g.DrawImage(i, New Rectangle(0, 0, Request("width"), Request("height")), New Rectangle(0, 0, i.Width, i.Width / Request("width") * Request("height")), GraphicsUnit.Pixel)
        Else
            ' landscape image processing
            g.DrawImage(i, New Rectangle(0, 0, Request("width"), Request("height")), New Rectangle(0, 0, i.Height / Request("height") * Request("width"), i.Height), GraphicsUnit.Pixel)
        End If

        Dim encoderParams As System.Drawing.Imaging.EncoderParameters = New System.Drawing.Imaging.EncoderParameters
        Dim quality As Long
        Dim comp As Integer = 0
        If Not (Request.QueryString("comp") = "") Then comp = CInt(Request.QueryString("comp"))
        quality = comp ' 0 to 100 - 100 highest quality
        Dim encoderParam As System.Drawing.Imaging.EncoderParameter = New System.Drawing.Imaging.EncoderParameter(System.Drawing.Imaging.Encoder.Quality, quality)
        encoderParams.Param(0) = encoderParam

        Dim arrayICI As ImageCodecInfo() = ImageCodecInfo.GetImageEncoders()
        Dim jpegICI As ImageCodecInfo
        Dim x As Integer
        For x = 0 To arrayICI.Length - 1

            If (arrayICI(x).FormatDescription.Equals("JPEG")) Then
                jpegICI = arrayICI(x)
                Exit For
            End If

        Next

        If Not jpegICI Is Nothing Then
            Thumbnail.Save(Response.OutputStream, jpegICI, encoderParams)
        End If

        'Response.ContentType = "image/jpg"
        'Thumbnail.Save(Response.OutputStream, ImageFormat.Jpeg)
        'i.Save(Response.OutputStream, ImageFormat.Jpeg)

        Thumbnail.Dispose()
    End Sub

End Class