Basically what the title says: I've found some images that are already uploaded here from FA that have a higher resolution available via Twitter with the :orig tacked on the end. However, the Twitter version has a much lower file size from compression, but you can't tell the compression unless you zoom in up close.

Would it be better to upload the ones I've found from Twitter or just leave the ones here from FA alone?

Thanks.

Filesize is irrelevant information and not useable as quality metric. e621 handles content by visual quality and closest to original copies are always preferred.

There's reason why both FA and Twitter are under unfavorable sources at top of howto:sites_and_sources, because both suck.

Twitter uses much higher compression values that FA does, but they do not scale the content down. Because FA uses relatively soft scaling method, usually this is enough for twitter copy to keep more information intact and thus better version.

Neither version are preferred and there are other variables, but in really many cases twitter copy has been better. You didn't link any examples so can't say for certain what this case would be.

Ah yeah I didn't link any examples, sorry about that.

https://pbs.twimg.com/media/DGBFfdBU0AE-9MP.jpg:orig
https://d.facdn.net/art/roy/1505577704/1505577704.roy_suicunensfw.png

https://pbs.twimg.com/media/DFVB9qHU0AAHbuL.jpg:orig
https://d.facdn.net/art/roy/1505014689/1505014689.roy_pets.png

https://pbs.twimg.com/media/DOQYg7RUEAAqxy8.jpg:orig
https://d.facdn.net/art/roy/1510544332/1510544332.roy_roy_solow.png

And yeah I do know about all that stuff, I'm a stickler for size and quality as well, but despite the artist's multiple galleries, these ones are only posted on their Twitter and FA.

JCV said:
https://pbs.twimg.com/media/DGBFfdBU0AE-9MP.jpg:orig
https://d.facdn.net/art/roy/1505577704/1505577704.roy_suicunensfw.png

FA lies about the file being PNG, it's actually JPG and twitter is WAAAAYYYYY much higher resolution so definitely Twitter.

JCV said:
https://pbs.twimg.com/media/DFVB9qHU0AAHbuL.jpg:orig
https://d.facdn.net/art/roy/1505014689/1505014689.roy_pets.png

This one's bit trickier.
FA version is actually PNG so there's no visual compression and that's preferred fileformat, but twitter version is much higher resolution. Resolution increase is so massive that I would almost say twitter version being better regardless of heavy compression.

JCV said:
https://pbs.twimg.com/media/DOQYg7RUEAAqxy8.jpg:orig
https://d.facdn.net/art/roy/1510544332/1510544332.roy_roy_solow.png

This is the prime example of what I said that FA downscaling is bit soft and once again, FA lies about file being PNG and it's actually JPG as well. Even if twitter has higher compression, you can see smaller details like eyebrows being mushed together in FA copy. Definitely would go with twitter copy in this case as well.

In all of these cases it seems like artist did submit them as PNG originally, which does make looking at these bit painful as they could easily force them to be PNG on both platforms with ease, but have decided againts it.