If she appears even larger (this is about life-size) it is not your imagination!
Spidey is very swollen--full of eggs!
As evidenced by the bodies littering the sill below, she was eating well (the remains of a fairly large grasshopper was testimony) but her web did look a bit messier than usual.
Two days later we were back at the lake and noticed a change!
And up in the corner of the window sash is a roundish object about the size of a buckeye.
(Yeah, lived in Ohio a bit too long.)
This is the egg sac. It is encased in a brownish webbing that is waterproof, and many strands of silk hold it firmly in place. There are about two dozen points where the spider tacked the silk to the glass surface.
And below, our writing spider is celebrating with a meal (a small grasshopper).
The grasshopper must have put up a fight, because there were holes in the web. By the next morning, the spider was well advanced in the process of 'weaving' a new web, moving from the outside of the orb, she was carefully placing the continuous spiral by attaching the strand of silk to every other radial. When she reached the center, she signed her work with a handsome zigzag.
I looked up the writing spider via Google. 'Black and yellow garden spider' and 'corn spider' are other names for Argiope aurantia. (Beware of Wikipedia; it claims that the web is constructed from the center out. As an eye witness, I can attest to the opposite.)
I feel privileged to have this spider here and to have watched her all summer long!