With Fireworks, you can import several file formats, including Photoshop, FreeHand, Illustrator, uncompressed CorelDRAW, and animated GIF files.
When you import a file format other than PNG using File > Open, a new Fireworks document is created. While the new document is a PNG file, the original file remains unchanged.
For information on importing graphics as image objects into an open Fireworks document, see Including imported images in a document.
In Fireworks 1, the background layer is a permanent image stretching across the entire canvas, under which no objects or layers can be placed. Fireworks 3 documents do not have a permanent background layer.
When opening Fireworks 1 documents in Fireworks 3, the background layer from the Fireworks 1 document is converted into an image object and is placed as a shared layer on the bottom of the document.
Also, the URL overlay in the Fireworks 1 document is converted to the Web Layer.
For more information about layers, see Creating and arranging layers.