Regarding this topic...I don't know for how long we have the possibility to see the source of the uploads in the queue (it is there for quite a while, though).
Since I don't really understand how this work, but apparantly if there is a source like this
http://i2.pixiv.net/img-original/img/2016/12/12/17/13/12/60347801_p0.jpg
then it is the normal size, am I right?
And if the source is like this
http://i2.pixiv.net/c/1200x1200/img-master/img/2016/12/12/00/13/09/60340849_p0_master1200.jpg
i.e. there is no "original" like in the link above, then it is a pixiv sample.
If that is correct, then if an approver should accumulate to many pixiv samples, maybe one should link them the the mod queue and look at the source (I should do that, too).
That said, if that is correct, then Janitors should be linked more often directly to the queue, because one can see there the source and doesn't have to look at the pixiv page.