I currently have Yosemite installed on my iMac - If I install the El Capitan GM will I loose all my installed programs and configuration or will it just do an upgrade?
Thanks in advance
I've heard from other users of the that they still have iPhoto and it still works. It's also available to download in the Purchased tab of the App Store. I've moved on to photos myself. It did take me a while to convert, but it really is so much faster. For some reason in Yosemite it locks up my trash. If I try to empty trash with Photos open it just locks up and won't empty until I close Photos app. On El Capitan, it works just fine.You should be fine, but keep in mind, that is possible that apps may "break" in an OS update. If you update correctly, it is unlikely that you would lose any documents or data.
One exception might be iPhoto, as it was replaced with Photos. You might lose that.