Can't transfer photos from iPod Touch to Photos in Yosemite

I have an iPod Touch running OS 6.1.6. Until now, I have had no problems uploading photos from it to my iMac, in iPhotos. Now the iMac is updated to Yosemite and the new Photos app, and I can't see any way to transfer photos from the iPod to the iMac.

When the iPod is attached by USB cable to the iMac, it is visible to iTunes, but Photos does not list it as a Device, and presents no Import option.

What can I do?