より多くのコードを含めるように更新されました。
vb.net 2012 では、未使用の変数を示す以下のコードに対して 3 つの警告が表示されます。temp、filetype、および inde はすべて未使用として警告されています。
Private Sub Next_Image()
    ' TO Do -  is same, maybe make a function? Don't know if its worth it though
msgbox(My.Computer.FileSystem.GetFileInfo(img_picture.ImageLocation).Extension)
exit sub
    If changes = True Then
        If filesettings(2) = 0 Then
            If MessageBox.Show("Save Changes?", "Save Changes", MessageBoxButtons.YesNo, MessageBoxIcon.Question) = Windows.Forms.DialogResult.Yes Then
                Dim filetype As System.Drawing.Imaging.ImageFormat
                If My.Computer.FileSystem.GetFileInfo(img_picture.ImageLocation).Extension.ToLower = ".png" Then
                    filetype = System.Drawing.Imaging.ImageFormat.Png
                ElseIf My.Computer.FileSystem.GetFileInfo(img_picture.ImageLocation).Extension.ToLower = ".jpg" OrElse My.Computer.FileSystem.GetFileInfo(img_picture.ImageLocation).Extension.ToLower = ".jpeg" Then
                    filetype = System.Drawing.Imaging.ImageFormat.Jpeg
                ElseIf My.Computer.FileSystem.GetFileInfo(img_picture.ImageLocation).Extension.ToLower = ".bmp" Then
                    filetype = System.Drawing.Imaging.ImageFormat.Bmp
                ElseIf My.Computer.FileSystem.GetFileInfo(img_picture.ImageLocation).Extension.ToLower = ".gif" Then
                    filetype = System.Drawing.Imaging.ImageFormat.Gif
                ElseIf My.Computer.FileSystem.GetFileInfo(img_picture.ImageLocation).Extension.ToLower = ".tiff" Then
                    filetype = System.Drawing.Imaging.ImageFormat.Tiff
                End If
                img_picture = Nothing
                imageadjust.Save(filename, filetype)
            End If
        End If
    End If
    If Not img_picture.ImageLocation = Nothing Then
        Dim inde As Integer = files.IndexOf(filename)
        If inde = files.Count - 1 Then
            img_picture.ImageLocation = files(0)
        Else
            img_picture.ImageLocation = files(inde + 1)
        End If
        filename = img_picture.ImageLocation
        Me.Text = filename.Substring(filename.LastIndexOf("\") + 1) & " - Picture Viewer"
        If filesettings(0) = 1 Then
            img_picture.SizeMode = PictureBoxSizeMode.CenterImage
        ElseIf filesettings(0) = 2 Then
            img_picture.SizeMode = PictureBoxSizeMode.Zoom
        Else
            Dim temp As New Bitmap(filename)
            Me.img_picture.Refresh()
            If temp.Width > Me.img_picture.Width OrElse temp.Height > Me.img_picture.Height Then
                Me.img_picture.SizeMode = PictureBoxSizeMode.Zoom
            Else
                Me.img_picture.SizeMode = PictureBoxSizeMode.CenterImage
            End If
            temp.Dispose()
        End If
    End If
End Sub
コードを許してください。追加を始めたばかりなので、冗長なものもあるかもしれません。しかし、temp、inde、filetype が未使用と宣言されている理由がわかりません。