Sorry been finishing up some custom jobs and sometimes forget what questions were asked.
I had meant to answer yesterday.
Um...
Permalink...
1. On my computer, i open up a photo, work on it, then save it with the name "horses-trotting-stock-photo.jpg.
So in essence..
horses-trotting-stock-photo.jpg has no effect on any names at all. During the processing a preview is created
using the title from IPTC data, and the main downloadable file name is replaced with an image number.
So like you say in #2 (unless I've missed something in my own coding)
http://www.cathyslifestockphotos.com/horses-trotting is named so because possibly your
IPTC title has the name horses-trotting, and that is what is being retrieved during the processing. If IPTC data is empty, it would be called something generic like "royalty free stock image" or something. The filename (not iptc, but the
filename...) is really irrelevant since it gets scrapped.
The IPTC data as you probably know is what you change when you alter your jpg image to contain keywords, description, and
title.
But just to reiterate if you were save as draft and change the slug to horses-trotting-stock-photo, then that would work out fine.