Feedback request on child post
I'm noticing a disturbing trend of posting a very slight variation of an art piece and calling it a child post.

While it is no doubt that this has to stop. I would like to ask for public opinion on what would be allowed before a child post should be approved.

I'm having a few ideas for childpost:
detext or uncensored
fault removal (scanning artifacts, paper texture, watermarks, or paper scramps)
better version (digital vs scans, high resolution)

Your inputs are welcomed.

In the meantime, please don't spam the site with slight variations as child post.
It should be in context of the content. Most of these child posts are just variations of the elements present and the situation (which is almost always sexual).
Considering the experience obtained from game CG's, I'll try to express it in a table according to content.

Content/Variations allowed
Content | 1 / 2 / 3+

background/ | Y / Y / Y
characters present

Different | Y / Y / X

Clothes | Y / Y / X

Underwear | Y / X / X

Situation | Y / X / X

Sexual | X / X / X
elements(organs, liquids)

Censorship | Y / X / X

I hope I cover it all. Variatons that fall under X should be considered Useless variation.
I'd like to add a question: A set of images should be parented to only one post, by not allowing children of children? As, I've seen, the large quantity of variations can comprehend situations in which users do this.
To me a child post is one that is next in line in a sequence of images. EG: First image has picture of girl dressed in a bikini. First child post has her without her top on. Second child post has her without her top or bottom on. Ideally these should be posted in the sequence's order. This should not, however, include pictures with tiny differences. EG: The girl with the bikini now has her top with two stripes on one cup rather than three. The pic with the two stripes doesn't move the action of the sequence forward. An example of an artist (whom I actually like) who does this is Dandon Fuga. If we were to include all the pics of all his sets we would soon be in the tens of thousands of pics when, using the example I provided above, we could reduce that number to a mere few hundred. I also agree that a child post would be something like what Checkmate posited in his post.
Go for it.

As for limit, I don't mind any of the following (or combination of):

1. only one variant allowed.
2. only obvious different variants allowed
3. hard cap of 2 or 3 variants for each image.

As soon as we decided one consistent rule.
As for children of children, I'd say in general just avoid it. It's much easier to check all the variants if everything is parented to a singular post.

Unless there's compelling reason to do so (like a fixed version of a specific child post).
I think fireattack has it in a nutshell and I agree. Included with this, however, I would say that there is implicit in this that posters include, at a minimum, the artist's name and source of the picture so that those who want to see the variations can search for them on other sites. As far as what Checkmate has said I think those could also be regarded as child posts if the original post was posted a long time before and deleting the original would cause problems otherwise I'd say just delete the inferior copy in favor of the better one.
The child post are as follows according to my understanding:

Take this post for example:post #937064

When there are only two pictures:
The uncensored or high-definition original image of Fanbox can be used as a parent post:post #937064
The censored or low-quality preview image of pixiv can be used as a child post:post #935787
parent post---->child post1
post #937064->post #935787

When there are multiple pictures corresponding to the parent post and the child post:
post #937064 as a parent post,post #937065post #937066 these as child post.
post #935787 as a child and as a parent,post #935788post #935789 these as child post.

parent post---->child post1---->child post2---->child post3
post #937064->post #935787->post #937065->post #937066

parent post---->child post1---->child post2---->child post3
post #935787->post #935788->post #935789->post #935790

The uncensored or censored who are the child posts,I personally think that the uncensored can be used as the child post.