Currently, a perceptual has has to be added in rules/blobs.ts, along with associated labels.
phashes: ["e0e0e0e0e0fcfefe", "9b9e00008f8fffff", "f090889c9ede9ee6"],
label: "troll",
However, skywatch-tail computes the phashes for already labeled images (well, it should, but there may be some bugs to work out). Ideally, we could chain these tools together, so that skywatch-phash maintains a key-value db of unique "phash":"label" pairs that it can use to update it's own labeling criteria for matching against.