Continuing on this thread two years later.
I have a similar question. I have resized the featured image using the Simple Image Sizes plugin. I does work but only to a degree as featured image doesn’t allow to pick a size when you actually choose the image and therefore it will not work with retina images.

To be precise – Enfold featured images will not – as far I have noticed – work with the Retina 2x plugin by Meow Apps, simply because I have to choose the original retina sized image in the media library. The theme will then load the retina image at all times. This is of course not good, especially since an image that is too large will make the theme crop the image 12% in the top and bottom.

I have searched this forum, but there doesn’t seem to be a good solution for retina images on the featured image yet. The only solution I can think of is to insert a normal size image as a featured image – say 800×450.jpg and then manually place the (Email address hidden if logged out) in the uploads directory via ftp. I havn’t tried it yet though.

If I am wrong here or any one has come up with a better solution. I’d be happy to know about it.

Hi Ismael,
A confession: I wrongly assumed that the h1 tag on “posts” is used the same way as it is on “pages”. However Enfold outputs the h1 in a different way on posts. Therefore my requests are redundant. Everything is perfect and you don’t need to fix anything :-)
Thanks!
Björn