upload jpg/png/ gif photos - asp.net

Question

I was doing a test to upload pictures and i found out that when i upload pictures more than 2000px the webpage turn to be slow. I want users to upload pics with size not more than 600px and height 700px.
Imports System.Data
Imports System.IO
Imports System.Data.SqlClient
Partial Class PhotoAdmin_Default
Inherits System.Web.UI.Page
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
UserIdValue.Text = Membership.GetUser().ProviderUserKey.ToString()
cannotUploadImageMessage.Visible = False
End Sub
Protected Sub dvPictureInsert_ItemInserted(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.DetailsViewInsertedEventArgs) Handles dvPictureInsert.ItemInserted
'If the record was successfully inserted, save the picture
If e.AffectedRows > 0 Then
'Determine the maximum pictureID for this user
Dim results As DataView =
CType(maxPictureIDDataSource.Select(DataSourceSelectArguments.Empty),
DataView)
Dim pictureIDJustAdded As Integer = CType(results(0)(0), Integer)
'Reference the FileUpload control
Dim imageUpload As FileUpload =
CType(dvPictureInsert.FindControl("imageUpload"), FileUpload)
If imageUpload.HasFile Then
Dim baseDirectory As String = Server.MapPath("~/UploadedImages/")
imageUpload.SaveAs(baseDirectory & pictureIDJustAdded & ".jpg")
End If
End If
If e.Exception Is Nothing Then
' Use the AffectedRows property to determine whether the
' record was inserted. Sometimes an error might occur that
' does not raise an exception, but prevents the insert
' operation from completing.
If e.AffectedRows = 1 Then
MessageLabel.Text = "Record inserted successfully."
Else
MessageLabel.Text = "An error occurred during the insert operation."
' Use the KeepInInsertMode property to remain in insert mode
' when an error occurs during the insert operation.
e.KeepInInsertMode = True
End If
Else
' Insert the code to handle the exception.
MessageLabel.Text = e.Exception.Message
' Use the ExceptionHandled property to indicate that the
' exception has already been handled.
e.ExceptionHandled = True
e.KeepInInsertMode = True
End If
End Sub
Protected Sub dvPictureInsert_ItemInserting(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.DetailsViewInsertEventArgs) Handles dvPictureInsert.ItemInserting
Dim cancelInsert As Boolean = False
Dim imageUpload As FileUpload =
CType(dvPictureInsert.FindControl("imageUpload"), FileUpload)
If Not imageUpload.HasFile Then
cancelInsert = True
Else
If Not imageUpload.FileName.ToUpper().EndsWith(".JPG") Then
cancelInsert = True 'Invalid image file!
End If
End If
If cancelInsert Then
e.Cancel = True
cannotUploadImageMessage.Visible = True
End If
'Set the UserId value to the currently logged on user's ID
e.Values("UserId") = Membership.GetUser().ProviderUserKey
'Set the UploadedOn value to the current date/time
e.Values("UploadedOn") = DateTime.Now
End Sub
Protected Sub gvPictures_RowDeleted(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewDeletedEventArgs) Handles gvPictures.RowDeleted
Dim baseDirectory As String = Server.MapPath("~/UploadedImages/")
Dim fileName As String = baseDirectory &
e.Keys("PictureID") & ".jpg"
File.Delete(fileName)
End Sub
Protected Sub gvPictures_RowUpdating(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewUpdateEventArgs) Handles gvPictures.RowUpdating
e.NewValues("UserId") = Membership.GetUser().ProviderUserKey
End Sub
End Class

Answer 1

Setting a max width and height on an uploaded image isn't necessarily going to fix your problem as you could upload an image with a much higher DPI and it still be a "large" image with small dimensions. Also, you would have to check the image dimensions once the image had been uploaded to your server.
You could set a maxiumum file size in the web.config using the maxRequestLength property which could be used to prevent a large file being uploaded...

Answer 2

Sorry if my vb is wrong as im a c# guy!! but I hope this should give you a guidance. I do something similar in c#. Good luck
Protected Sub dvPictureInsert_ItemInserting(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.DetailsViewInsertEventArgs) Handles dvPictureInsert.ItemInserting
Dim cancelInsert As Boolean = False
Dim imageUpload As FileUpload =
CType(dvPictureInsert.FindControl("imageUpload"), FileUpload)
If Not imageUpload.HasFile Then
cancelInsert = True
Else
If Not imageUpload.FileName.ToUpper().EndsWith(".JPG") Then
cancelInsert = True 'Invalid image file!
Else
Dim image As System.Drawing.Image =
System.Drawing.Image.FromStream(imageUpload.PostedFile.InputStream)
If image.Width > 600 Or image.Height > 700 Then
cancelInsert = True
End If
End If
End If
//etc