Here is a Photoshop plugin for reading and writing Alias .PIX format files. I wrote this in 1995 for Photoshop 3.0 but fortunately Adobe has not had a reason to change the plugin format so it should still work.
If you need just the plugin download this file, unzip it, and put it in your Photoshop Plugins directory.
If you want the source code it's here:
I'm sure portions of it are copyright Adobe. Feel free to do anything you want with both the source and the executable. I gave this to Alias back in 95 but as far as I know they never passed it on. If you add anything cool tell me and I'll post a link to your version here.
Of course no warrenty expressed or implied etc. etc. Use at your own risk.