:Slide.Image.Width: becomes the slide image width you've specified in PPT2HTML's Preferences dialog. :Slide.Image.Height: becomes the image height (which PPT2HTML calculates for you).

:Slide.Image.Width: is particularly useful when you also want to use the :Nav.Map: placeholder to add a clickable image map to your html pages. For the map to work correctly, you have to be certain that the size of the image specified in your template and the size you specify in PPT2HTML's preferences dialog are identical. Otherwise the clickable imagemap links don't line up with the original buttons they're created from. Ooops.

So instead of specifying an image width or height in your template, use :Slide.Image.Width: and/or :Slide.Image.Height: like so:

<IMG SRC=":Slide.Image:" WIDTH=":Slide.Image.Width:">

PPT2HTML substitutes the image width you chose in the preferences dialog for :Slide.Image.Width: so you can change the image size in the Preferences dialog without having to edit your template.

If you prefer, you can use :Slide.Image.Height: instead, or even both, but there's no need to. :Slide.Image.Width: alone is enough.