Overview of customizing an item's icon
By default, when an item is displayed in the Modeler panes, Property Pages and Link Editor, the item uses the icon associated with its type.
For some items in the model you may want to use an alternative icon. You can do this by changing the style settings of the item - either through the item or through a Stereotype.
Through a Symbol Style—A Symbol Style allows you to change the icon for all items of a specific model item type. Create a Symbol Style that specifies the icon you want to use, and then apply the Symbol Style to the appropriate model item type. All items of the specified model item type will use the icon in Modeler panes.
Through an item—You set up style settings for an item through its Property Pages. On the Style tab, click Edit to open the Style Modification dialog, and then select an icon through the Select button on the Icon tab.
Use this method when the icon you are using is used only for the item or maybe for a few other items.
Through a Stereotype—You can specify an alternative icon for a Stereotype and then apply that icon to items through the Stereotype.
Use this method when you are using a Stereotype to subtype an item and you want all subtyped items to use the Stereotype's icon. Alternatively, use this method when you want the Stereotype's icon available for items in the model.
For more information about applying icons to items through Stereotypes, see Overview of using alternative item icons and symbols through iconic stereotypes.
When you select an icon to use, you must select a Windows icon (ico extension). The icon file requires a small and large version of the icon.
When you set up an alternative icon through an item's Property Pages, the alternative icon is always used for the item.
If an alternative icon is not specified for an item, Modeler searches each applied Stereotype in turn for an alternative icon:
If no alternative icon is found, the default icon for the item's type is used.
If an alternative icon is found, Modeler uses that icon. You can order the applied Stereotypes on the Items tab of an item's Property Pages.
* 
Selecting the 'Apply to All Objects of Associated Model Item Types' check box for a Stereotype does not apply the Stereotype's symbol style to any items.