Question about the quality of my deleted wallpapers

I've been getting a lot of wallpaper deletions lately and decided to clarify the reasons so I can better share wallpapers in the future. I'm new here. please forgive me for causing trouble for the moderators, but I'm also open to learning and working on my mistakes! Here some of my links:

1. Link: https://wallhaven.cc/w/m3zjqy
   Reason: Low quality
   My question: I thought the noise here was added for artistic value. Isn't it?

2. Link: https://wallhaven.cc/w/x6zq8o
   Reason: Low quality (Full of compression artifacts.)
   My question: I only see a little noise at high zoomlvl. It looks fine on my 4k monitor, so I thought I'd share it. I didn't think it was high levels of JPEG/compression artifacts as in rules?

3. Link: https://wallhaven.cc/w/o5yo9l
   Reason: Low quality (Full of artifacts.)
   My question: The image is a little noisy when zooming. Can I for example resize it to FullHD, will that remove the noise?

4. Link: https://wallhaven.cc/w/gp5rzq
   Reason: Low quality (Artifacts / upscaled / poor camera.)
   My question: Can you point to artifacts, for example by circling them in red? I only see low-level artifacts at high zoom. Can I descale the wallpaper and upload it again?

5. Link: https://wallhaven.cc/w/l8z6y2
   Reason: Low quality (Compression artifacts around edges.)
   My question: Thank you for pointing out the location of the artifacts, yes, I agree that there are small edge artifacts in microchip. Is this enough to remove, while they are not visible when using the picture as wallpaper? Can I remove them by reducing the resolution to FullHD and reup the wallpaper?

   I'm not trying to deliberately upload low-quality wallpaper, just I have this wallpapers on my 4k monitor and it looks decent...

The compression artifacts are mostly visible near hard edges. The noise itself isn't a problem, but when it is too much due to compression it gets distorted, hence the low quality. And yes, you can say that most of there problems appeared because of the very high resolution - compression algorithms make artifacts more visible at higher resolutions.

lumberjacck thanks for the clarification, it's clearer now. I experimented with downscaling and found that by reducing the image dimensions by /3 or /4 (from 4000x4000 to 1500x1500 for example), the artifacts at the borders disappear. I'll try to re-upload (after descaling ofc) my old hi-res wallpapers, which was deleted due to low quality (artifacts), if I find time.

Glad to hear.