Setup Retina Ready Images

Add images 2x the size of their normal view for retina screen compatibility
For both your slide's Main Background and Image Layers

1. Background Images

Upload an image to WordPress 2x the size of your slider's Layers Grid size.
Then set the Image Source Size to "Original Size" and the Background Fit option to "Cover".

2. Image Layers

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Add an Image Layer to the editing stage:
Next, lock the aspect ratio for the layer size:
And finally, resize the image down by 50%