Macbook pro retina 15 – image resolution problem

Hi. Good to see you.
I have a question about ‘image resolution’.
Before that there is to know first. This is very important.
I am using the “mabbook pro retina 15”.

I have to upload an image file on my website,
created the image file to the “adobe photoshop cc”.
This image (= jpg and png) file, which is a lot of pictures and the statements made by the various text.

I am the horizontal size of the maximum length of the theme you are using is 1200 (px).
I have uploaded an image file as it once was.
iMac and a standard PC in the resolution of the image file looks normal.

But !!
In “mabbook pro retina 15”,
The clarity of the text within the image file is very low.
In WordPress can solve this problem?
Can I do to solve this problem?