Optimisation : send smaller images (or avoid sending some images) to mobile devices

google rankings are becoming more focused on mobile devices.

Site speed for websites viewed on mobile devices will increasingly determine overall search engine rankings


We need to make sure that no unnecessary content is delivered to them



So, instead of sending the same hi-res images that are sent to a laptop/desktop, we should send images of reduced dimensions to mobile devices (eg, slider images, product pictures,category images...)


also, is there css/scripts loaded unneceserily to mobile devices ?




also, i've noticed in some themes, sometimes instead of displaying an image - for example an image for a category - just the category name is displayed (which is good i think) but, is the image loaded anyway and just not displayed ?

It would be better practice i think if it were not loaded

also, 'recently viewed pages' if images are enabled - i'm sure there are other instances ....

so,

https://github.com/nopSolutions/nopCommerce/issues/508#issuecomment-289202356

would help to address image loading times



it relates to svg support - for more info :
https://en.wikipedia.org/wiki/Scalable_Vector_Graphics