Using Symbols, Instances, and Library Assets > Symbols, instances, and library assets overview |  |

Symbols, instances, and library assets overview

A symbol is a graphic, button, or movie clip that you create once in Macromedia Flash MX and can reuse throughout your movie or in other movies. A symbol can include artwork that you import from another application. Any symbol you create automatically becomes part of the library for the current document. (For more information on the library, see Using the library.)

An instance is a copy of a symbol located on the Stage or nested inside another symbol. An instance can be very different from its symbol in color, size, and function. Editing the symbol updates all of its instances, but applying effects to an instance of a symbol updates only that instance. You can also create font symbols in Flash. See Creating font symbols.

Using symbols in your movies dramatically reduces file size; saving several instances of a symbol requires less storage space than saving multiple copies of the contents of the symbol. For example, you can reduce the file size of your movies if you convert static graphics such as background images into symbols that you then reuse. Using symbols can also speed movie playback, because a symbol needs to be downloaded to the Flash Player only once.

You can share symbols among Flash movies as runtime or author-time shared library assets. For runtime shared assets, you can link assets in a source movie to any number of destination movies, without importing the assets into the destination movies. For author-time shared assets, you can update or replace a symbol with any other symbol available on your local network. See Using shared library assets.

If you import library assets that have the same name as assets already in the library, you can resolve naming conflicts without accidentally overwriting existing assets. See Resolving conflicts between library assets.

You can also add ActionScript actions to symbols. See Writing Scripts with ActionScript.

For an interactive introduction to using symbols and instances, choose Help > Lessons > Symbols.

A symbol in the library and two instances on the Stage, with effects applied to the instance on the right