Recently uploaded a piece of pixelart (https://e621.net/posts/2322519) but noticed that many other images in the pixel tag are upscaled 2×, 3× or sometimes like 5× times. My animation did some out pretty tiny, so I can see why people would do that. For future reference, is there a good rule of thumb for how much upscaling is desirable? Should I be aiming for a certain resolution? Thanks, let me know!

uploading_guidelines#bad

Small images: Anything below 200px in either direction is likely to get deleted

So the problem with pixelart is that modern displays have more and more pixels in higher density, meaning that what was acceptable on NES, is starting to be almost invisible with some displays, I can fit like 10 SMB sprites under my pinkie fingernail on my current monitor. So to see the image, you have to zoom it and sadly almost everything including browsers usually use some generic purpose upscaling method like bilinear, which essentially blurs out the pixel detail. Also do note that this is a guideline, so people have tried to upscale their 10x10 pixelart to 1000x1000, but it has still been deleted for resolution as 10x10 is obviously really tiny no matter how much you upscale it.

We have near zero tolerance to upscales, especially thanks to rise of tools like waifu2x and topaz gigapixel, because usually scaling images up or down will destroy some of it's detail. Exception to this is of course pixel artwork, because as long as you use integer and nearest neighbor/no filter scaling, visual detail of the image stays exactly the same and you can reverse the change with ease.

There is nothing else written as rule or guideline other than what is given above: essentially if the image is size of thumbnail, it's most likely getting deleted, anything above is fine resolution wise. If I were to say rule of thumb, I guess it's to make the artwork to be visible on modern displays. Our sample version size is as of writing this still 800px dimension max, so that should be considered to be big enough upscale (also people using sample mode won't then get downscaled upscale). Some artists (and I) do like pixel artwork the best when the pixels aren't clearly square, so some include 1px scale next to upscaled version, that is acceptable and entirely up to you if you want to do that or not.

And of course if you do use lossy video formats, 2x or 4x are highly recommended thanks to chroma subsampling.

Try to get close to a 1000x1000 resolution, but avoid resizing it by over 5x or so

mairo said:
uploading_guidelines#bad
So the problem with pixelart is that modern displays have more and more pixels in higher density, meaning that what was acceptable on NES, is starting to be almost invisible with some displays, I can fit like 10 SMB sprites under my pinkie fingernail on my current monitor. So to see the image, you have to zoom it and sadly almost everything including browsers usually use some generic purpose upscaling method like bilinear, which essentially blurs out the pixel detail. Also do note that this is a guideline, so people have tried to upscale their 10x10 pixelart to 1000x1000, but it has still been deleted for resolution as 10x10 is obviously really tiny no matter how much you upscale it.

We have near zero tolerance to upscales, especially thanks to rise of tools like waifu2x and topaz gigapixel, because usually scaling images up or down will destroy some of it's detail. Exception to this is of course pixel artwork, because as long as you use integer and nearest neighbor/no filter scaling, visual detail of the image stays exactly the same and you can reverse the change with ease.

There is nothing else written as rule or guideline other than what is given above: essentially if the image is size of thumbnail, it's most likely getting deleted, anything above is fine resolution wise. If I were to say rule of thumb, I guess it's to make the artwork to be visible on modern displays. Our sample version size is as of writing this still 800px dimension max, so that should be considered to be big enough upscale (also people using sample mode won't then get downscaled upscale). Some artists (and I) do like pixel artwork the best when the pixels aren't clearly square, so some include 1px scale next to upscaled version, that is acceptable and entirely up to you if you want to do that or not.

And of course if you do use lossy video formats, 2x or 4x are highly recommended thanks to chroma subsampling.

Cool, thanks for the detailed write-up! It seems my image did get approved this time despite being 200×145, but in the future I'll see if I can at least do it 2×. I do also like the look of un-upscaled pixelart, so I guess I can put a link in the description/source.