Hello people of the interwebs and of the e621 forums (derp)

I basically have a question about the 'minimal standard requirements' on images that can be uploaded. I've seen a few takedowns on images not meeting the quality, I know its typically either very small images or sketches, but to what extent does this count?

I'm currently uploading the works of Amazin-Arts- as his stuff isn't up here and he has given me permission to do so - and I know his detailed, coloured works are fine, i know this. But he has a large number of sketches like the following:
http://amazin-arts.tumblr.com/image/130075073597
http://amazin-arts.tumblr.com/image/129896096427
http://67.media.tumblr.com/6c0738a64634bf21f50a062077521a20/tumblr_nv3v83CDtK1u9vkzio1_1280.png
http://amazin-arts.tumblr.com/image/140618001727

Only a few examples but, I know images like this are fine - being more detailed and such https://e621.net/post/show/1011315/-3-amazin-arts-anal-anal_penetration-animal_genita

and I am not talking about images like http://amazin-arts.tumblr.com/image/129657626817 as they are too 'sketchy' and not quality

How detailed should a sketch be to technically allowed on here? Or is there a thing on this site basically talking about this in more detail, and I just missed it?
I'd rather ask than do strings of sketch uploads, and have them pulled down

Thanks in advance

the quality standards refers to image's overall artistic quality, not the amount of details or how much the artist has spent time on the piece. the art in those sketches is good so i dont see why it would not meet the minimum quality standards.