Passing User Credentials to SSRS

[rgp34]

Hi, I am trying to check if an image file exists. If it does exist then use it, otherwise, use a default image. I am trying to pass integrated windows login credentials to get a response but I always return false. It seems to not like the credentials. Does anyone have input here? Thanks in advance!

Here is my code:

PS - All this code is done inside the Custom Code of SSRS

Function IsValid(ByVal Url As String) As Boolean
        Dim URLRes As Net.FileWebResponse
        Dim URLReq As Net.FileWebRequest
        Dim myURI As New Uri("file://www.example.com/" & Url & ".jpg")
        Try
    URLReq = Net.FileWebRequest.Create(myURI)
    URLReq.Credentials = Net.CredentialCache.DefaultCredentials
    URLRes = URLReq.GetResponse()    
    Return True
        Catch ex As Exception
            Return False
        End Try
    End Function