Usually for events like this we are able to download the art made as wallpapers or at least the full resolutions have been made available for us. This Snowdown is sadly lacking in that, I want to deck the halls with images of the Poro King or an Orianna nutcracker splash art. Excellent job with the art by the way!
If you want a picture from Riot news, right-click it and hit 'view image'. Then hope the resolution is right. If not, google it and use the search tools to search for your desktop resolution (for example: https://www.google.nl/search?q=poro+king&biw=1920&bih=979&tbm=isch&source=lnt&tbs=isz:ex,iszw:1920,iszh:1080 )
http://promo.euw.leagueoflegends.com/assets/snowdown-2014/teaser/img/snowdown-teaser-image-1080.jpg Here's the kingless one, 1920x1080.
http://i.imgur.com/bup3GEK.jpg Kingful one, 1920x1080
http://euw.leagueoflegends.com/sites/default/files/styles/scale_xlarge/public/upload/winter_wonder_orianna_splash_1920.jpg Winter wonder Orianna at 1280x720
