JarateKingCaydaLooks like they just did a quick google search for the images they're using. Kind of lazy, but can't really blame them if they don't know anything about TF2 or 6s.To be fair to multiplay, it looks like they did that for each game (the only image I can't find quickly in a search is league's), so I don't think it's any particular ignorance about tf2.
It would be nice to have an online resource or ZIP file of more appropriate, competitively-oriented promo images that could be sent to website staff when they are advertising a comp TF2 event. Or maybe something like that already exists? Haven't really looked.
Getting some good resources for things like this sounds like a great idea though. The talent in this community is too good for generic beta screenshots to be used :/
someone should make a post on /r/tf2 or something getting a small community drive for competitive or "serious" looking thumbnails and promo images going. A lot of SFM wizards are over there but don't come here.