Yes, you can. In addition to changing the look in Preferences-Furniture Icon in plan, you can also use your own. However, it involves using the Furniture library editor and editing the library manually to insert a planIcon reference. You need, of course a .png file and a reference in the file [font=courier new]PluginFurnitureCatalog.properties[/font]. Have a look at thread 7832: Improve quality of top view image in 2D plan and thread 2582 Add picture on 2D panel only. I am sure there are better and more instructive threads, but cannot find them right now.

I find custom planIcons very useful, especially for staircases (showing direction) and using semi-transparent icons for furniture like awnings where you also want to be able to see through the icon.