Simply put the 'car.png' into the 'Images' folder in the Steam Directory of MSC. (C:\Program Files (x86)\Steam\SteamApps\common\My Summer Car\Images)
Then go to Fleetaris Shop and select 'Custom Paint Job By Artist'
Or something like that.
Metallica Skin for Satsuma 1.0
Cool Metallica Skin For Your Satsuma So You Can Headbang While Going 200 KM\H.