In said:
It's not. Although my knowledge of image compression techniques is
somewhat limited, I believe the total size of an image will generally go
*up* by splitting it in two, especially when HTTP headers are added. The
are some exceptions probably.
Yes. It makes sence, if you have something like low contrast photo/color-
glide on background and small logo/text on the other end. Then when you
save photo using jpg and logo using png, and can get serious size
reduction.
(as you can use much higher progression for jpg and logo with few colors
as png don't take much)
Of course, in such case, it was wrong to do image as one from beginning.
Of course, you do gain an advantage with two images: the browser can
download them simultaneously, which could result in a small speed gain.
And, you can make it wrap... Something like this:
http://www.student.oulu.fi/~laurirai/www/css/examples/img_after.html
It fits very narrow window. (but I don't think it makes sence just
because size reduction, that is pretty small, IIRC 1.7kB)
(I'm having problem with antialias on wrapped image, as I got that image
ready made, so it is not easiest task to change...)