I have servel image sizes in my post, all under 2 proportion: square and rectangle.
for example square :100X100, 200X200 rectangle: 300X100, 600X200
Via ACF I created new image upload file so I can upload one proportion via ACF and one proportion via 'post-thumbnails'
How can I control add_image_size function so the rectangle resize will make from the rectangle file and the square resizes will make from the square size