Yes…, although this “philosophy of tiddlers” norm is always contextual, right? Something should get its own tiddler if it is likely to be called upon for re-use, if it needs to be separately searchable, etc. In a wiki devoted to students, however, it would make sense to put the profile pic for a student into that tiddler — when the image “belongs” quite directly to a tiddler, it’s easier to transclude it as a tiddler-field pair than to try to remember whatever other naming scheme one might have for image-associated-with-x… and also one doesn’t have to think separately about whether dragging a tag-pill-worth of tiddlers might leave something behind that in some sense “belongs” to them.
At any rate, I’m looking forward to experimenting with this!