Yes, I think it is likely that Egan would file the online license for this image with Getty, since he states on his website that he is distributing the images though Getty Images. Egan being from Ireland should not make any difference if he filed, what he thinks, a legal license with Getty in the U.S.?
I would assume Egan thinks he's doing whatever he needs to do to sell in the US. But he may be following Getty's advice (which could be mistaken) or he may merely think the extra he can make in the US doesn't merit his registering copyrights himself in the US. (Getty seems to have led some photographers to believe this-- and then have lost cases in court owing to courts interpreting US copyright law differently than Getty.)
But there are two different issues:
(a) registration of the copyright. Registration would be filed with a government agency: e.g. US copyright office, Irish copyright office and so on.
(b) licensing the right to use the copyrighted content. Licensing would be a contract between the copyright holder (often the photographer) and the user or reseller (which could be Getty.)
The two are separate actions. The copyright holder could have granted a perfectly valid
license to Getty in the US. But the registration might be flawed or nonexistent.
The total damages Getty or the photographer could recover in a suit is affected by whether the image was
registered prior to any unauthorized copying. In US law, a copyright holder can get actual damages if the image was not registered prior to unauthorized copying but they can get statutory damages if the images was registered. The latter can be much higher and often drive the very scary numbers in the letters Getty sends out. We have pretty good evidence the photographer does not register his photo's in the use-- but he may register them in Ireland. I just don't know how such registrations are treated in US courts. (I don't know because I'm inexpert!)
Whether Getty has standing to sell licenses and pursue unlicensed copying for the copyright holder depends on whether the
license(i.e. contract between the copyright holder and Getty) is valid. I'm sure the photographer has gone through some motions filling out forms and paperworks with the intention of creating a license with Getty. However, it's not clear that judge would interpret these licenses as valid in court. The reason is that-- at least in the past-- Getty seems to have set things up in ways that don't ensure the paper work is sufficiently clear, properly signed and so on. So, some of Getty's cases might be thrown out on the grounds that Getty doesn't have standing to sue because the license doesn't really hold water. If Getty's license is flawed, then Getty couldn't sue you on behalf of the photographer-- but the photographer could sue you ( if he wished to bother.)
Getty has in the past had difficulties
both with respect to flawed licenses and with respect to flawed copyright registrations. To prevail in a suit, they need to fix both. They may have done so. We don't know.