Upgrades for my G4 iMac(flowerpot)

[Laroosco]

Want to set the machine up for my mother. She will use it to check email and display pictures with.
I want to upgrade the hard drive and install the newest OS possible. Checking online I'm getting a lot of contradictory advice.

If I remember right, the iMac was made in late 2003. It originally had 256 RAM, but I did a 1GB upgrade. Currently running 10.3

Thanks for any help.

 

[AdrianK]

You can see the upgrades available for your model here. Use About This Mac to get the CPU speed.

 

[Laroosco]

Thanks