So I decided to move the subject here for an official discussion and so that everyone can read. If you think the preferred priority for character infobox image is not satisfying enough, pls go ahead and share your opinion. You might think this is just a minor matter but actually it's not, so do speak up until we find the most compromising method. The current priority, which seems to satisfy most ppl, is:
Remake > Original > Spin-off > DLC/Spotpass > Other materials.
I still think we need to sort out things like the old TCG or Treasure art, where something from "Other material" is used alongside Original artwork (such as Thracia 776 just reusing the Treasure art for returning FE4 charas who never join the player's army) or as equivalent to such (such as the FE Museum using TCG art for pretty much all SNES era games). That's a kinda grey area in terms of classification we need to clarify I feel.
Otherwise, yeah, I do think that is pretty much spot on. For example: Folks will want Marth's headline image from his most recent game where he headlines, not his Awakening artwork where his design is (recursively) derived from Lucina's and done by a guest artist, nor his old Dark Dragon art which is an outdated depiction of the character.--Otherarrow (talk) 16:59, March 9, 2017 (UTC)
You're right. Then how about we separate artbooks and they should receive higher priority than spin-off:
Remake > Original > Artbook > Spin-off > DLC/Spotpass > Other materials (TCG, manga, comic etc.)