I am using tex4ht to create a document in HTML and my images are PNG files. For tex4ht I need eps images although in the final HTML page I use original PNG files (see my other question here on tex.se).
So the idea is to use a dummy eps image of a certain width and height (the size should not matter, as the final image is replaced anyway).
The current situation is the following: for every PNG image, I need an EPS image with the same name, for
htlatex (DVI mode) to find it. The EPS is never visible to the user, it is only used internally. So IMO it is not really necessary. I would like to avoid the extra steps to create the EPS file and the double disk space (I use a lot of images).