Update config-default.yml
Update config-default.yml

Consistence naming of the folder "images", so pictures will be now compressed in production. The folder "img" doesn't exist by default.
davenaylor/FoundationPress,bellatl/FoundationPress,linuxbastard/FoundationPress,davenaylor/FoundationPress,bellatl/FoundationPress,linuxbastard/FoundationPress,olefredrik/FoundationPress,randmanrjr/FoundationPress-randman,randmanrjr/FoundationPress-randman,colin-marshall/FoundationPress,olefredrik/FoundationPress,colin-marshall/FoundationPress