Hi, It would be better to show a label for the pointer shown in the linear gauge. As without the label, it would be difficult to interpret the exact value of the pointer.
Add tooltips and background images/borders to the Gauges. The current way of setting the background image using CSS works but is somewhat complex. Setting a border on the gauge does not surround the shape of the gauge, but rather results in a square. Allow a border around the gauge's physical shape (for example, in a half circle radial gauge, the border is around the half circle), or some nicer built-in backgrounds/borders.