When you create a tool, the tool is added to a tool palette with the icon of the tool from which it was copied or with a default icon. You can change the tool icon by selecting a new icon saved as an image file or by selecting an object in the drawing. You cannot create icons from custom blocks. If you need to create an icon based on a custom block, save the block as an image file in any of the formats in the following list.
Sample tool icons
When you change a tool icon by selecting an icon saved as an image file, you can use any of the following image file formats:
Icons in tool palettes can have a maximum size of 64 x 64 pixels. Larger images are scaled when inserted.
To replace the tool icon using an image file
To replace the tool icon using an object in a drawing