Another day...and you seem to have it fixed, however.
(1) I f you scale an asymmetric image, this case the width less than the height, without breaking the link between width & height then the result is also asymmetric (you got 148 x 256)
(2) Scale and break the link between width and height to give a 'square' image (256 x 256) and the image is distorted, in this case the width is stretched.
(3) As previous post, increase the size of the canvas to 'square' before scaling down to...256 or 64. example: https://i.imgur.com/4UDcym2.mp4 or in your case merge with a 'square' layer, either way the canvas size rules.
(1) I f you scale an asymmetric image, this case the width less than the height, without breaking the link between width & height then the result is also asymmetric (you got 148 x 256)
(2) Scale and break the link between width and height to give a 'square' image (256 x 256) and the image is distorted, in this case the width is stretched.
(3) As previous post, increase the size of the canvas to 'square' before scaling down to...256 or 64. example: https://i.imgur.com/4UDcym2.mp4 or in your case merge with a 'square' layer, either way the canvas size rules.