Pictures in videos look blurry in YT with 480p

[hello0]

Hi,

so whenever I put pictures in my videos, when I watch them in Youtube, with 1080p they look perfect, but with 480p, they look always blurry and with bad quality.

I save the pictures in .png because I need them to be transparent.

The pictures size is always small, like 200 kb. i dont know why, even though I draw them in 4000 pixels size,

the pictures are drawings that I draw in PS. Is it because of that, because its drawings?

its not just pictures, its Fonts as well.

Do you have any solutions how I can make the pics look fine with good quality when watching the Vids in 480p?

[jagabo]

So you can't see why reducing the resolution to 1/10 of the original might make the picture blurry?

[hello0]

I dont know, when I watch other peoples videos, the pictures never get that blurry, so i thought it must have something to do with how I save my pictures with a too low resolution?

Maybe I should save the pictures with a size of 1 MB and they will look better afterwards in the videos?