Query Active Directory (using sAMAccountName) and Return A Thumbnail Photo

ActiveDirectoryThumbnail.fs

    open System.DirectoryServices

    /// Gets a user's thumbnail photo from active directory. Returns null if no image found.
    let ActiveDirectoryImageFor(samAccount:string):byte[] =
        use adSearcher = new DirectorySearcher()
        adSearcher.Filter <- "(&(objectClass=user) (sAMAccountName=" + samAccount + "))"

        let adResult = adSearcher.FindOne()
        if adResult = null
            then
                null
            else 
                use adUser = new DirectoryEntry(adResult.Path)
                let adJpeg = adUser.Properties.["thumbnailPhoto"]
                let adImageData = if (adJpeg.Value :? byte[]) then adJpeg.Value :?> byte[] else null

		adImageData