I am using 4.1 since February. In my installation there is no setting key named sevenspikescommonsettings.lazyloadimages. When i add manually there is no difference.
I just download 4.2 theme. I searched this setting key and nothing.
I searched also emporiumthemesettings.lazyloadimages key and i found one usage at .\Emporium\Views\Shared\_ProductBox.cshtml
var lazyLoadImages = settingService.GetSettingByKey("EmporiumThemeSettings.LazyLoadImages", false, storeId, true);
Similar code is in 4.1 version. May be i am missing something but also there will be a bug in there. Because when i switched this setting something happening: dissapper all images???
We planned to have theme specific settings initially but then decided to do it as a general setting that will be automatically enabled and used in all themes and plugins so that you don't need to set any settings manually.
This is how the latest version of Emporium theme in 4.1 and 4.2 works.
The code for the theme specific setting in Emporium in 4.20 is there but not really used and we will remove it (sorry for the confusion).
Simply update the theme to the latest version
in 4.1 (even better if you simply upgrade to 4.20
) and everything will work fine just like in our demo store.