Pro Version > Image installation not same as instructions

I have a pro version of the plugin, if you don’t recognize my name that’s because I’m the developer for the client who purchased yesterday. Her first name is Carol. Anywho…

As I follow the instructions for the Pro version…

I am using a Genesis Child Theme and setting the Featured Image in the Genesis theme settings. This image size is added in functions.php as add_image_size( 'featured-image', 760, 360, TRUE );

The biggest image I have set for the website is 760×360. I have set Large in Settings > Media to 0x0.

After I upload the full-size image which is a retina-sized image of 1520×720 (Note: 720px), the plugin is asking me to add a retina-sized image of 3040×1520 (Note: 760px), showing ‘red’ in the Full-Size retina column of Media > Retina. Why is it doing this? This 1520×720 image is the Full-size/retina-size file! It’s also telling me that the full-size image should be 1520×760? Where does this number come from? I have no file size that size or even half that size set in Settings > Media or even in the functions.php file. Again, the biggest file size I have set for the website is 760×360, and I’m uploading 1520×720.

Additionally, the other file sizes (Featured-Image, Medium, Thumbnail) show ‘blue’ in the Media Sizes Retina-ized column, which is good. In the Uploads folder this 1520×720 shows as myfile.jpg as well as myfile-760×[email protected] (which is 1520×720) and as myfile-760×360.jpg, along with the Medium and Thumbnail sizes I have set for the site, and these also have a ‘@2x.’ So all of the correct file sizes are there except that myfile.jpg (which is 1520×720) appears to be causing the Media > Retina panel to indicate that I still need to upload a Full-Size Retina image as that column has a ‘red’ square. Shouldn’t this square be ‘blue’ at this point?

The instructions indicate that if I upload a Full-Size image given the file name myfile.jpg (without ‘@2x’) that it will take care of everything, and so it shouldn’t be showing in the Media > Retina panel. Why is this showing? How is it supposed be? Again, it’s telling me that the full-size resolution should be 1520×760 when I have correctly output and uploaded the full-size image as 1520×720, how and why is it adding these extra 40px and telling me it should be this way? Something isn’t right here. What is going on?

https://ww.wp.xz.cn/plugins/wp-retina-2x/