Sankaku Channel/quality versus difference, a question about deletion

I stumbled about these examples:
http://chan.sankakucomplex.com/post/show/333172
http://chan.sankakucomplex.com/post/show/337769

First picture is slightly different, but has lower overall resolution/"quality".
Second one got the doujin name, but higher resolution.

Example#2:
http://chan.sankakucomplex.com/post/show/1191582
http://chan.sankakucomplex.com/post/show/1704490

First picture lower, 'cropped' version of the second one.
Second one has a spine.

Before I was a Janitor, I just parented them. But now I keep thinking too much about cleaning up. Personally, I would delete only Example#2, but I am not sure about the first one. I talked to System about this issue, and the situation with duplicates is really clear, but not for these examples here. (For those who want to read it: http://chan.sankakucomplex.com/wiki/show?title=duplicate )

Well, I could keep focusing just on duplicates and ignore these issues/keep parenting them, but I thought I just ask for some opinions.

For Example#2 I honestly think the JPG has better quality than the PNG…

Ah, I don’t think Example#1 should be deleted. One is even censored, while the other isn’t, although you can’t really tell because of the low res…

These are obvious examples of "good" duplicates. Are the guidelines still not clear enough about them?

First two are clearly different versions of the same image and so are not even duplicates as such. Second example is raw image versus slight crop, which is fine as well.

The only ambiguity is over which is the parent... first case I would say the big jpg is likely the parent whilst in the second the "best" version would make the obvious parent (a detexted cropped version if it were extant) with all derivatives and the original or less processed versions as children.

System said:
These are obvious examples of "good" duplicates.

That somehow cleared my mind, thanks!
Updated the guidelines with a small addition.

What about these 4?
http://chan.sankakucomplex.com/post/similar?id=3301517

Deth deleted two of them, I would restore them.

Restoration would be consistent with our policies, yes.

Any way to remove the flags as a Janitor? I see a little approve button in the flagbox, but it doesn't do anything with the flag.

It is not yet clear whether this is down to a problem with the system or a problem with flags made prior to the latest iteration. In principle you should be able to clear the flag as janitor.

Ah, so it's this one again. I was looking through the "Moderate" list if these posts had appeared, but they didn't. I'll check again. My OCD flagpost magically apperead on the top of the list later on.

Guess I can just post here.

Can someone tell me what the difference between these two pictures is? Their size differs slightly, but the pictures look the same to me.

Post #3692889
http://i1.pixiv.net/img31/img/extinct_canis/24952556_big_p6.jpg

Should the post be deleted and replaced by the Pixiv original or what in this case? Normally you can actually see some compression differences between the images, but for this one I don’t see any so I’m not sure whether it should be replaced or not.

I've heard that Pixiv started running various optimisers (the usual stuff - stripping metadata and losslessly compressing them) on originals which causes the sizes and md5s to differ with no actual change to the image. This may be such a case, with the change having occurred after it was originally grabbed from Pixiv.

I think there is no real need to replace in this case, but I don't see any reason to object to it either.