Sorry i was not clear in my question. When you ask a designer for theme the designer designs it in Dreamweaver (i think in the past) nowadays they give the design they have in mind using a psd file. How does this work.?
> @Jason nowadays they give the design they have in mind using a psd file.
It is like we do in PowerPoint. Photoshop allows to make mockup web pages much more easily than coding. So if we want to `draw`` a theme to show the designer, we can do it in Adobe Photoshop like make slides in PowerPoint.
Another advantage of using a PSD is that there are tools which can convert a properly prepared PSD file into HTML and CSS.