Well, you are correct about me having the wrong aspect ratio, but 4:3 might not be right either.
Back when I first took this screen shot (it's a couple of years old now), the emulator I was using for the captures didn't even support changing the aspect ratio. It saved all the screen shots as 1024x1024 squares.
So I was guessing a bit at the actual correct sizes and got it slightly wrong.
I need to recapture some of those old Generations screens in a better resolution to fix that.
As for 4:3, in the time since I wrote that description, I've learned that the game's native resolution is apparently a widescreen ratio. A recent screen shot that a newer version of the emulator claims to be the native resolution is something like 10:7. It's freaky.