Well you're singling out Lezim when he wasnt even the one who uploaded the pic to the wiki. The guy I mentioned was the one who did. So yelling at Lezim would do nothing since he wouldn't know the source in the first place.
Nah, we don't have such policy; images are uploaded left and right in the wiki; if we delete an image just because someone wasn't citing it source when using it, I'd say 90% of the images (not really) in this wiki will be deleted.
That being said though, it's a good etiquette to know from where your image is taken, and credit them if it's a fanart not drawn by you.
EDIT: For official pages though, fanarts are forbidden. Fanarts drawn by respective card artists will go to Official Extra Art Gallery.
Just cause you delete it from your profile doesn't mean that it's gone from the wiki. Drew's problem of taking artwork and uploading it without credit still stands (just not at you, though. You should be fine.)