Aw you made this post faster than I did.  I'll post the images that aren't the same as yours.

i would say 16 gen, Neo Geo especially

Overall, 4th gen is the oldest I can go back to without some graphics issues. 3rd is good, but quite a few titles suffer from flickering, lack of color or detail, and too often you can see the devs struggle with hardware limits right on screen.

As far as 3D goes, 6th gen, although it definitely has problems on bigger monitors.

N64... Is the most amazing graphics than I saw in my entire life...

The SNES era. Whichever era that is. But for modern era I voted for the GCN era. Those graphics could stand up even to this day without issue.

Some 2D games could really benefit from higher resolutions or higher resolution sprites and 3D games from 5th gen look beyond horrible so the minimum I'm willing to graphically accept is the 6th gen ...

I would say the 6th gen. Though for the most part certain games on the GameCube I was not impressed with, but it was or should I say still is the gen that has aged best.

I don't think anything before the Sixth gen shouldn't count cuz those Graphics are going to stay the same at least from what I can tell

Starting with the 4th gen/SNES era there were games that aged stupidly well... And others. Not so much.
Case in point: Donkey Kong and Killer Instinct have aged well. StarFox? Not so much.

On the Nintendo 64, Smash Brothers still looks decent. Golden Eye? Nope.

On the PS1, Final Fantasy 8 still looks great, mostly thanks to the pre-rendered backdrops.

So for me, it's not really the generation so much as the art and technical techniques used to render the games... Besides being a PC gamer you tend not to look at things in generations anyway.

a lot of NES and SNES games have aged extremely well simply because the art style at the time often was attempting a cartoon/comic book esque look. They rarely WENT for realism because they knew it would be impossible

I mean there are loads of NES and SNES games that are equally replayable today as they were then. Mario Bros or Legend of Zelda for the NES could be made today and be equally as accessible. hence why so many people want these games on mobile (not that I want that), they're easy to play and get into for all ages and still look good.

now, granted, there are some 3rd/4th gen games that looked terribly but I would argue any generation has bad eggs.

the Atari gen is pretty much the only one, in my opinion, where there are virtually no games that have really lasted. Naturally that was early testing groundsd for gaming so

I prefer the 4th gen myself, but... Dude, Little Samson, Kirby's Adventure, Batman, Super Mario Bros. 3 and the late Mega Man games are masterpieces on NES.