Ghost has always been sold on the basis that one license is used for one machine, and has never been sold on any other basis.
My experience, we had a license for Ghost and that was it, there was no need for an image license or such
That's certainly how a lot of people used it, especially around 1996/97 when "shareware"-type trial downloads were available - people would conveniently just forget about the fact that they were supposed to stop using it, or would just ignore the license terms and use it without caring, but the fact is that the actual EULA and license terms for genuine Ghost back all the way to at least 1996 actually stated that one paid license was to be used on one machine only, and one license was needed for every machine deployed.
It's the case that Symantec does have special licensing programs for larger customers; programs like this are common for all kinds of software in the Fortune 500 world, and rather than force customers to pre-pay can let customers use unlimited numbers of copies on the basis that you can do an annual "true-up". Many of the OEM licenses for Ghost used for computer manufacturing over the years worked this way, because do to it otherwise would have required the manufacturer to know how many machines they would build (OEM computer manufacturer licenses are also one-shot, to be used to image a machine one time, and not perpetual multi-use licenses as the standard one).
These programs were designed for computer manufacturers and people doing large volumes of business (20,000 seats and up, or manufacturing millions of PCs annually), at the kind of scale where the price breaks drive the costs very low.
[ One of the things that made it hard for our team when we were initially designing and building out the GSS - then "Ghost Enterprise" - management capabilities was that around 2000 due to these OEM licenses, management perceived the average sale price for Ghost was less than one dollar per license thanks to these special one-time-use manufacturer licenses. Since a fair few of the people higher up the management chain weren't particularly numerate, there was pushback on us developing the console management system because it was to them clearly pointless when our "average" price was so low; trying to explain to the innumerate folks that computing an average between a vast-volume one-use license type and one where we could deliver a lot more value to corporate people with a perpetual license and that was where we had the future market growth was ... hard. ]
So, it's simple. For every machine you want to use Ghost with, you need a license. The price you pay for those licenses decreases drastically with the number of machines in question, and over a certain point may or may not need to be prepaid (the specifics of the larger license programs change a lot over time, as large companies like Symantec have to adhere to all kinds of very particular accounting rules for things like when revenue can be booked, so you do always need to deal with an account manager to get up-to-date information on what license programs you qualify for and what terms they have).
Something that was not explicitly spelled out in the older EULAs was what happened when a machine was retired, but later on in response to customers wanting a definite clause for it the rules were formalized into the GSS EULA to explicitly state that if a machine deployed with Ghost was "put beyond use" (i.e. the disks had failed or were wiped) then the license that was conceptually "attached" to the machine by having it deployed with Ghost could be considered reclaimed and you could attach it to some other physical hardware.
The one other aspect of licensing that was not historically an issue and which was not specifically addressed in the GSS EULA was the case of virtual machines, and the precise accounting for Ghost deployment to virtual machines. While we had our thinking on that, that's an area which has become a larger and larger factor over the recent years and while I participated in most of the licensing discussions around Ghost from 1997 through to 2010 (as I wrote a lot of the licensing-related code in the product), the thinking on that subject may be different now and if that's an issue for you, you again need to discuss it with an account manager to get an "official" word as there wasn't an explicitly stated position on that in the past.