Canvas Resize w Fixed Aspect Ratio based on Height or Width

[gorgmd]

I have a batch of images, that all have different dimensions and are trimmed, so that the object in the picture "touches" all borders (left, right, top and bottom).

In the end I need them all with the same aspect ratio (1:1,6) - so I will have to resize the canvas, but I also want to maintain the maximum resolution that´s possible. How can I do this in a batch process?

I could of course first resize all images heights to the height of the smallest image (543px) and then calculate the width (543px * 1,6), but this would also mean, that many of the really highres images get downsized tremendously (what I want to prevent, since there are some that have a height of more than 3000px).

Is there a function where I can say - resize the canvas, set the canvas width to 1,6 of the images height, expand canvas only? I have not found an answer in the forum - so please appologise, if am asking an already known and answered question.