"Export for Twitter" Unexpectedly Affects PNGs?

Hi, I was working on non-animated portraits. I made two versions of my character, one at 64x64 and one at 128x128 with more detail. When I exported them as PNGs, I decided to check “Export for Twitter” on the 64x64 version just to see what would happen. I posted both versions on my Twitter and my carrd website portfolio. They both looked clear on my Twitter, but on my carrd the 128x128 version had artifacts visible both on PC monitor and iPhone screen.

I thought it had to do with the 128x128 version being bigger and having more details, but artifacts appeared on the 64x64 version as well when I unchecked “Export for Twitter.” Scaling the export up or down did not seem to have any effect on the artifacts.

This is a side-by-side view. As a new Aseprite community user, I can only attach one piece of media, so I hope this will suffice. Please right-click and “Open Image in New Tab” to make it easier to see the difference:

The first PNG was exported with the “Export for Twitter” option checked, while the second PNG was exported without the “Export for Twitter” option checked. All other export options were the same. Only the second PNG has artifacts. They are most visible in the middle, at the “staircase” pixels.

I am confused because the Aseprite documentation and previous threads regarding the function of this option suggests that “Export for Twitter” only affects GIF animations: “Adjusts the animation to avoid some problems on Twitter reproducing the last frame with an invalid delay.” However, it seems like if I want to showcase my work on my carrd website portfolio with clarity, I need to check the “Export for Twitter” option to prevent artifacts from showing up.

I am just curious about what is happening since these are PNGs and not GIFs, and I could not find a thread about this. I think this would be considered an “unexpected” thing that Aseprite is doing, so I hope this report is of use!

[v1.3.2 Steam, Windows]

its not unexpected, it changes the way tje image is formated so when you post on twitter doesnt fuck it up, due to its wonky image treatement, its on purpose.

Thank you for your response.

It was “unexpected” to me because the Aseprite documentation seems to suggest it only affects GIFs: “Adjusts the animation to avoid some problems on Twitter reproducing the last frame with an invalid delay.” and all previous threads I read about this option talks about GIF animations only.

It would be helpful if the documentation was updated to clarify what is actually happening to an exported PNG using “Export for Twitter” instead of just GIFs if that is the case. An added line suggesting users to always check the option to avoid artifacts displaying on certain websites would have saved me some confusion.

I must also reiterate that the images showed clearly on Twitter when I posted them. The artifacts appeared on the PNG that was not exported with “Export for Twitter” checked on my carrd website portfolio.