How to increase resolution of uploaded game icon

My Issue
I was quickly making some sample icons to see how they would look and noticed an issue. When uploading into roblox, the resolution gets downscaled and some parts of the image look extremely blurry.

Any way to avoid to avoid this downscaling in rendering or editing? If not, any tips in thumbnail and render creation to have the highest quality thumbnail possible?

Examples
My image is 512x512. I tried uploading a 1024x1024 version but that showed the same decrease in resolution.

This is the reulting image. that appears in the thumbnail.

i dont think theres a way to get past this.

but hey, the icon is still very legible even after the downscaling! shouldn’t be a problem.

Thanks. will stick with this for now. Also readability drops a lot when I add rainbow elements to the logo. any workarounds?

The .jpg format is better for sharing images, but the .png format is better for editing images. I recommend using the .jpg format for your game logo or thumbnail.