~~Title: Icon Sizes ~~ As already mentioned, each icon set can contain one or two distinct groups of icons. For simplicity, these are referred to as the `small` size and the `large` size. However, you are not limited to only two sizes of icon-only two groups of icons. It is possible to have different icons of multiple sizes within the one group. For example,   Note that both `set` nodes above have the `size` attribute set to `small` This example would add two icons to the `small` group – one, called “copy” that is 20x20 in size, and one called “move” that is 24x24 in size. Even though they are different physical sizes, they would both appear together in the `small` group for this icon set. The icons you provide in the `small` and `large` groups do not have to correspond – you do not **need** to provide both small and large forms of every icon (although it is obviously better for the user if you do.)