[RESOLVED] Detecting Invalid Images?

[formlesstree4]

Ok, I have a program that parses INI files (yes yes, I know, but I'm stuck with using them, not my own request), and it downloads external images (if the INI contains the path) to the program and cache's them.

Recently, I've run into a snag with the system. Most of the images use Imageshack for storage, but one of them has suddenly 404'd, and whenever I set it to the picturebox to the downloaded image, I get an out of memory error rather quickly (and the file itself is 1kb).

I guess I need to implement a checking system offline to find out if the image is actually an image or just a '404' text...but is there a way to not have to implement this clientside, and have it be checked when I download it?

Here's the downloading code:

Public Function DownloadImageStream(ByVal ImageURL As String) As MemoryStream
        Dim objImage As MemoryStream 'Create a MemoryStream
        Dim objwebClient As WebClient 'Create a WebClient
        Dim sURL As String = Trim(ImageURL) 'Remove any leading/ending spaces
        Try
            'Add the http:// if needed
            If Not sURL.ToLower().StartsWith("http://") Then sURL = "http://" & sURL
            'Initiate the new WebClient
            objwebClient = New WebClient()
            Dim url As Uri
            url = New Uri(sURL)
            'New MemoryStream from downloading the image
            'from the specified url
            objImage = New MemoryStream(objwebClient.DownloadData(url))
            'Return the Image from the downloaded Stream
            Return objImage
        Catch ex As Exception
            'custom error handling, don't worry about this.
            Dim err As New default_ErrorDialog
            err.ThrowError(ex.Message, ex.StackTrace, ex.InnerException.ToString)
            Return Nothing
        End Try
    End Function