When you make a new slide, choose a layout with an 'object' placeholder. Don't select 'insert, object' and directly insert the assembly since it will make your Powerpoint very large. Put the picture (created using one of the methods above) in that spot. Then, if you want to be able to bring up the assembly in SolidWorks, you can make a hyperlink to it. Highlight the picture, or maybe a piece of text, right-click, select hyperlink, then browse for the file. That way your Powerpoint stays small, but you can launch the assembly if you need to.