Photos / iPhoto

Hi,

In answer to your first question, there seems to be no easy way to move Mail attachments to Photos -- maybe it's a bug in Yosemite 10.10.3. However, if you click on the paperclip in the Mail message, you get the option to Save or Export to iPhoto. If you Save to a desktop folder you can then drag the attachment to Photos. Also, in Mail > File, there is the option to Save Attachments.

If you choose Export to iPhoto, that will happen if you have iPhoto enabled. Or a window may pop up asking you to choose a photo library. Maybe if you choose the Photos Library that will work.

As to the second question(s), you can choose to continue using iPhoto, but it will no longer be supported by Apple, so sometime in the future you could have problems. Photos is part of OS X and cannot be deleted, so you would just ignore it. Photos has a lot of good features so it is worth giving it a try.

You can switch between Photos and iPhoto by changing the designated library. Designate a System Photo Library in Photos - Apple Support

The libraries do seem to be cumulative and take up disk space. I would recommend putting the ones you're not using on an external disk. http://osxdaily.com/2011/09/05/move-the-iphoto-library/

Hi again,

Just to straighten out the info I gave you about the photo libraries taking up disk space, which was wrong.

Photos uses the same master files as iPhoto or Aperture, so you won’t need double the space to run both apps.

Check out the article below, it's full of useful stuff, including a great gadget for upgrading old iPhoto libraries.

Get started with Photos for OS X - Apple Support

Lots of the work I've done in the past on Face recognition has been undone

What went wrong? All your iPhoto "Faces" data will still be in the original iPhoto library so it's not lost.

In Photos, in the sidebar, if you click on Faces, the faces you previously listed -- in iPhoto -- should show, and at the bottom, there will be a row of "suggested faces." If you double-click on one of those, add a name in the window that appears and click continue. A whole bunch of photos will be shown, with a circle around the person's face, so click "Add and continue."

there's a lot of photos in Photos that I'm quite sure I have previously deleted.

When you deleted them in iPhoto, did you empty the iPhoto Trash afterwards? If not they may have got carried over.

If you go to your iPhoto library in Users/Home folder/Pictures and double-click on it you get the option to open it in iPhoto or Photos. Choose iPhoto and see if your faces are in order there. Then close iPhoto and open Photos while holding down the Option key. Choose the iPhoto library and if all your faces are there you can designate it as your system photo library. Designate a System Photo Library in Photos - Apple Support