storing photos of my iPad and iPhone

Why not sync them with a computer and create a backup of those files then?

 

Why not create a dedicated user account on the iMac for this iPad specifically and only sync with content that that user account has access to?

 

Why not open a folder on the desktop and name it whatever you like, and then plug in the device to the computer and open Image Capture.....the images on your camera roll will then show up in Image Capture, and you can then copy them to the folder on the desktop. After that you have the option of leaving the material on the device or deleting it from there. The files will now be on your desktop in that folder and you can put the folder wherever you choose.

 

I use FileBrowser, which allows me to transfer photos directly to/from my NAS. I have a lot of photos.

 

Well, yes, it is a manual solution. I do not use iPhoto/Photos and never have. When I take images with my digital camera I import the images from the memory card to a folder on the desktop, similar to the process I use when I want to back up my camera roll, and then from there take the images into Aperture, which I am still using. So, yes, Image Capture works well for me as it does not restrict my later placement of the images from Camera Roll in any way. I don't use faces and places or whatever that is called but I am pretty sure that Image Capture does retain the basic EXIF of each photo, which would include time and date.

 

It means I am not locked into whatever iPhoto/Photos does and do not need to keep my images stored within its confines.

 

Use iCloud Photo Library?

 

You can have multiple Photos libraries under the same account. I do this and have separate libraries on my Mac for the kids photo libraries. Just hold down Option while opening Photos to create a new library or select an existing one.

 

You can use DS File also.

 

this. or you can create two Photos Libraries.