Hi blazevic.is,
add_image_size( 'slider-wide', 1440, 500, true ); // used on Featured Slider on Homepage Header for wide layout
Just replace the above code with
add_image_size( 'slider-wide', 1960, 550, true ); // used on Featured Slider on Homepage Header for wide layout
Once before using download the regenerate thumbnails plugin and regenerate the thumbnails. Hope that may help you.
Thank you!
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