PNG vs JPG in /a/

As anyone using /a/ has noticed, people still keep posting PNGs in cases JPGs would be much better. And now some are just doing it for trolling purposes... I don't care about my connection, because I have no download limit cap and have a decent one, but what about 4chan's bandwidth (which is already 100% in use CONSTANTLY) and people on slower connections?

So what do you guys think... warning bans to people for posting PNG screencaps or remove PNG support from /a/ altogether? Because PNG is mostly useful for wallpapers -> /w/ or high resolution stuff -> /hr/.

american out of Japan!!!!!!（￣Ａ￣）;;;

In my home country, this is Nara of japan, american student
1.stealing stuff everything
2.lyingto policeman
3.spit to face when talking, mouth is bad smell
4.dont having money, many american student, hole in cloths and dirty pants, old shoes
5.raping jap gal because jap gal say american boy no thanks, very ugly and fat
6.very smell of food eating by american
7.very smell body, no bath long time, sometime 10 days?
american=monkey same same