Surprise when I saved my pictograms for the Web (from Photoshop):
They are strictly not as clean as expected => totally blurred.

Reading over the web, I read that Retina screens expect each element to be built at a specific resolution.

Assuming that my elements are made using vectors (thanks to Illustrator), what would be an efficient way to fit my Retina display? For instance, an iPhone 6.

I read so many distinct solutions from the web that I don't know what are the most usual steps that graphic design experts deal with.

Surprise when I saved my pictograms for the Web (from Illustrator):
They are strictly not as clean as expected => totally blurred.

Here's an example from my Retina smartphone:

And the initial .ai file:

The difference is obvious...

Reading over the web, I read that Retina screens expect each element to be built at a specific resolution.

Assuming that my elements are made using vectors (thanks to Illustrator), what would be an efficient way to fit my Retina display? For instance, an iPhone 6.

I read so many distinct solutions from the web that I don't know what are the most usual steps that graphic design experts deal with.