Palettes are built from task templates.  A task template can be any subselection of a Maple worksheet (or an entire Maple worksheet).  It can include placeholders similar to those used in the Expression palette.

For information on this step, see Creating Tasks.

To define a Snippets palette, use the command DocumentTools[AddPalette].

You can specify where the palette appears in the Maple window (left or right, top or bottom).  To change this later, see Arranging Palettes.

Save the desired image as a PNG file.

Use the command DocumentTools[AddIcon] to store the icon in the same help database file as the associated task (by default, the tasks.hdb file).

To add the palette item to your palette, use the command DocumentTools[AddPaletteEntry].