Alamy has a huge collection.
Eyeem port will be dissolved in that ocean.
It all depends on search placement.
I am not sure how many images are available to Getty Images but somehow the EyeEm images get seen enough for many contributors to report sales. Not a huge amount of sales but on a regular basis. The images sourced from EyeEm represent a different style and look, so Getty mixed in some of them into their search results along with clean stock images.
I assume Alamy is going to do the same. If they didn't feel they could need those images in addition to the 60 million they have plus the ones they source through their own Stockimo app, why would they have made that deal.