I have downloaded a set of photo's my wife took at the weekend on to my iMac in photos. All the photos percolated onto my iphone6 and both our iPads in photo stream, I deleted them from my iphone6 and now they have disappeared from both my iPads. They are still on my iMac but how do I stop any photos I delete on one device deleting off the other devices?
That is normal behavior for the iOS devices. If you delete them on one iOS device, they are deleted on all iOS devices. Once the photos appear in the photo stream on the iPads or iPhones, you have to save them from the Photo Stream to the camera roll.
Launch the Photos app and tap on the Photo Stream Album. While in thumbnail view, tap Select in the upper right. Tap on all of the photos that you want to save in order to select them. Then tap on the action/share icon in the upper left. Then tap Save Images. The photos will be saved to the camera roll.
Many thanks for that info, also can I reload pictures in "photos on my imac" back on to my other devices???
You can sync photos from Photos, iPhoto, or any other photos folder that you have on the Mac. See the section about syncing photos manually with iTunes.
Keep your photos safely stored and up to date on all your devices - Apple Support
photo stream
