Essas imagens foram negadas por problemas de artefatos, o que são artefatos? esses granulados ao ver a foto em 100%? Are they very well treated? How can I improve this? paying attention to the ISO at the time of the photo? I'm starting now!
And this is denied by not conforming, is it because there are many equals?
Usually, if an image has been rejected for being non-compliant and there is a person in it, the rejection is because there is no model release or the model release is incorrect.
Generally speaking, it is better to sell full color photos on Adobe Stock. Since the vast majority of people are using Adobe Stock images in Photoshop, they can easily turn things black and white if they want to, but it is very difficult to add color to a monochrome image!