Game spiking when wallpaper changed

I've been having this weird two problems which are started one month ago. 1 - I have little lag spikes once in awhile that freezes game for 0.5 sec. 2 - My ping become high and I can't move my champion or do anything for 0.5-1 sec at the start of the game (till ~15+- minutes pass) This happens ONLY in summoner rift. I played a lot of ARAM and never experienced this even once. I've played some TTL and also haven't experienced this, but it was just few games per month so I can't tell.

The thing is. I figured out first issue cause - it's wallpapers which are changing in background. I have three monitors and I noticed that when my wallpaper changes - little lag spike appears in SR. I still can't figure out why my ping raising cause it's not cause of this and it's not cause of latency (game telling me that I have 60-65 ms and no FPS drop all the time). Also I noticed that a lot of people complain about same thing - they also experiencing this ping jumps for no reason.

SO I would like to know if I can do something with this. I don't want to change my wallpapers shuffle off, cause it will just be stupid to turn it on-off just to play the game (although I will try if this help). But more than ever I want to get rid of this high ping jumps. It's not cause of my LAN (I checked) and not cause I'm losing signal or downloading or opening browser with videos. Its happening even if I'm just playing LoL SR with no other programs open.