[RbnJrg]

Originally Posted by ElMiko

Thank you, RbnJrg.

FWIW, I suspect that the non-cover, full page images I'm dealing with may often behave somewhat similarly to cover images in that I tend to place them either at the end or beginning of a chapter as a separate html file to avoid sudden gaps in the text.

If you are working under epub2, that it's not a bad idea.

Also, in your example

<div class="wrapper">
   <svg...><image.../></svg>
</div>

does the unspecified styling in the <svg> tag have to include the specific pixel height and width of the image?

Yes, it does; you have to include the specific pixel height and width of the image. But that is trivial because Sigil has a plugin that makes all the work for you You only has to select the image and the code is generated by the plugin. To work with svg wrappers is not a problem at all.

Or can the aspect ratio be preserved without going through the trouble of looking up the true dimensions of each individual image (again, this is in reference to portrait mode images).

For each image you must have a particular svg wrapper since all your images have different dimensions. But I repeat you, that is not a problem for you; the Sigil's plugin will do all the work, you won't have to write any line of code (the plugin will write the pixels for you).