Any special optimization is done for retina slideshow images ?

Envato Authors Theme Authors
1

I use a Macbook retina display and I guess, mostly everyone uses the same.
I was checking many themes on theme forest, the slideshow images look crisp and they are very light weight too.
They load up immediate and looks perfect.

But when I do the images, they look a bit pixelated.

I was thinking, if there some kind of special optimization or settings done while making slideshow images these days ?

2

All our uploaded images are soft-cropped 2560px wide and we set them as background image so they scale properly on any resolution.

3

Slideshow image as background image ?

And what effect do you use to pop out the slideshow text part ?

I guess, some black fade or something ?
Is that a photoshop addon ?