Saving Resized Image Files To Server

I am trying to save some resized images to the server. Why I get the following error on the vSmlImgFle.Save(vTmpDir.ToString & vFile.Name, ImageFormat.Jpeg) (in red below) line?

A generic error occurred in GDI+.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.Runtime.InteropServices.ExternalException: A generic error occurred in GDI+.

And while we are on the subject of dealing with image files, is there a way to get the file format from the original file, rather than looking at the file extension to determine the file type:

If Ext = "JPG" then
Type = ImageFormat.Jpeg
Else if Ext = "JPG" then
Etc.

I thought that vImgFormat = vOrgImgFle.RawFormat might do it but that seems to return something completely different than ImageFormat.Jpeg.

Code:
Protected Function CopyScaleImages(ByVal FileSet As FileInfo())
Dim vTmpDir As New DirectoryInfo(Server.MapPath("~/SanInspPhotosTemp/"))
Dim vDir As New DirectoryInfo(Server.MapPath("~/SanInspPhotos/"))
Dim imgHght As Integer

[Code] .....