Just change the size of the picture in Photoshop if it“s huge. It would take you 10 seconds to do this, and just set the DPI to, let“s say, 180-240. Or more, your choice. Done.
By the way, I only work with newspaper design, which doesn“t involve 10 meter wide banners. I don“t know if that changes anything. It might.
EDIT: Well yes it must. That file size would be crazy large. Don“t know how to deal with that type of stuff.
I think saving as PDF, rather than EPS, also decreases the size somewhat, but changing nothing to the work or file. We save in PDF all the time. But I might be wrong about the size decreasing though.