I wonder if there is a way to upgrade to 10.6 so I can upload photos from my new Canon camera and install the software from the camera. Online, it appears that they just offer the Lion upgrade and my computer is too old to upgrade to that. Is there an older upgrade that I can purchase to get me to at least the 10.6?
iMac, Mac OS X (10.5.6), 2005 IMAC
If you're using a 2005 iMac, it's a PowerPC Mac and can't be upgraded past 10.5.8.
(82465)
So sorry, but no.
The highest OS X version your year and model iMac can take is OS X10.5.8.
Unless you really feel that you need to use the camera's software, you wouldn't need to have it; you don't need it since you can copy your images off the SD card onto your desktop and you can use iPhoto to do some light editing or there are plenty of other applications available for that task.
I am running Leopard 10.5.6 I just bought a camera and i need to be at 10.6
