A Domain license allows the control to run on 1 domain/subdomain name, ie http://news.domain.com or http://intranet or http://192.168.0.1
A Small Business License allows 10 such names
An IP license enables all the domains/subdomains hosted on this IP@ to use the control.
All license options are good for
http://localhost. I'd highly recommend Small Business License as it's the most popular choice among our customers. Out of the 10 names, you can use one or two for the internal dev server ie.
http://intranet while keep the rest for your production servers.
You are right. If you only have a few names to run Image Gallery on, there is no need to buy developer license. Developer license benefits a single developer with many sites.
Thanks for asking