I don't think the size is a key advantage here, even if it were true. 96 kilobytes simply isn't very big to start with, considering most of the content that gets sent around.
Like you said, support is what matters. SVG is notoriously difficult to implement and it took forever to be supported everywhere, which also contributed to the persistence of Flash. TVG is supposed to be easy to implement, which seems to be to be the advantage.
JPEG, by contrast, is a pretty simple format with only a few minor quirks.
If someone already implemented an XML parser for you, SVG is easier to implement than TVG (if you are trying to extract the same type of content out of SVG as out of TVG).
>if you are trying to extract the same type of content out of SVG as out of TVG
But then you haven't implemented SVG. You can't say "we support SVG", and you lack a good way to communicate what users can expect from your implementation. It's much easier to communicate clearly when you can implement a whole standard rather than a haphazard subset of one.
Also, parsing overhead is such a tiny fraction of the overall effort (in either case) it doesn't really mean anything.
Like you said, support is what matters. SVG is notoriously difficult to implement and it took forever to be supported everywhere, which also contributed to the persistence of Flash. TVG is supposed to be easy to implement, which seems to be to be the advantage.
JPEG, by contrast, is a pretty simple format with only a few minor quirks.