Changing button images for mouse over highlighting with a .NET ToolBar is a bit tricky.
This works with a little flicker, where %3==0 are normal images, & %3==2 are highlight images.
private void toolBar_MouseMove(object sender, System.Windows.Forms.MouseEventArgs e) {
foreach (ToolBarButton b in toolBar.Buttons) {
if (b.Style == ToolBarButtonStyle.Separator || !b.Enabled) continue;
if (b.Rectangle.Contains(e.X, e.Y))
b.ImageIndex = (b.ImageIndex / 3) * 3 + 2;
else
b.ImageIndex = (b.ImageIndex / 3) * 3;
}
}