.Enter new values for width and height, or click the “Fit into” pop-up menu and choose a size.
Resize the image by a percentage: Choose “percent” from the pop-up menu next to the Width and Height fields, then enter the percentage in those fields.
Force the image to keep its original proportions: Select “Scale proportionally.” If you change either the width or height, the other value changes to maintain the proportions. If you choose a size from the “Fit into” pop-up menu, the image’s width or height may be smaller than the chosen size to maintain the proportions.
Make the image’s dimensions smaller without losing any detail: Deselect “Resample image” before changing the width or height.
Tip: To resize multiple images at the same time, Crop or rotate a PDF in Preview on MacUse the Touch Bar