The one with the crepuscular rays definitely has a number of artifact issues.
For example, in the lower-right, you can see some severe blocking (image slightly enhanced:
The clouds look a bit smeary as if overly aggressive noise removal was used, but yet there's still a lot of noise in the image overall:
And, perhaps most damning, there is a lot of artifacting on the edge between the sky and land:
Also, it looks really blocky down there too, by the way. Those trees look like cubes.
Also, of course, it's very overexposed where the sun is and underexposed down on the ground, but that should be expected and not a reason to reject it. All the other issues, however, are reasonable.
The butterfly is borderline overexposed.
It is also fairly noisy when viewed at 100%. If the butterfly were properly exposed, maybe the noise wouldn't be an issue, but altogether it makes the image seem to be poor quality.
On the snake, the rocks are overexposed and the snake's face is out of focus. Neither of those are "artifacts" as there are exposure and focus issue reasons, but both of those issues would be reason for refusal.
Note how blurry his (her?) face is compared to how sharp the body is.
That's a problem. The eye on animals as well as humans should be in focus.
The flower (besides being fairly boring - there are THOUSANDS of similar compositions on Adobe Stock) is overexposed and demonstrates a lot of noise and artifacts:
If you want to prevent this sort of issue in the future, make sure you're viewing your images at full resolution. I've not blown any of these photos up. These are just crops taken at 100% zoom.
Does that help?
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