GLHDDS wrote:
... I have multiple Photos apps with different names but it seems ALL of them on the EHD are being uploaded to if I import new pics.
How are you working with Photos? It seems you are always importing to the same Photos Library, even if you are trying to open different ones.
The Photos.app is not containing your photos. Photos is storing the photos in Photos Libraries, as Tony described. If you are having several Photos Libraries, but all imported photos are always shown in the same library, Photos may not be able to access the other libraries, for example, if the are on a network share and not on a locally mounted volume, or on a volume used by Time Machine.
The size of the library should only matter and make Photos slow, if the hardware of your Mac is not powerful enough for large libraries, for example, if you are low on storage on your system volume, or the Mac does not have much memory.