The recommended way to import assets from a Photoshop PSD files since Dreamweaver CC 2014.1 is to use the Extract panel.
In older versions of Photoshop and Dreamweaver (CS3 and above), you can copy a selection or layer from a PSD in Photoshop directly into Dreamweaver (you need both Photoshop and Dreamweaver installed on the same computer). This launches the Image Preview dialog box for you to optimize and save an image ready for the Web.
If you can't copy from Photoshop into Dreamweaver, make sure that the Export Clipboard check box is selected in the Photoshop General Preferences panel.
Many thanks to Bob Levine for providing this useful tip.