Select the portion of the page you want to keep.
If you want to view the dimensions of the content you’re selecting, choose Tools > Show Inspector, then click the Crop Inspector button on your Mac, click the Show Markup Toolbar button on your Mac, open the file you want to change.
Choose Tools > Adjust Size, then select “Resample image.”
Enter a smaller value in the Resolution field.
The new size is shown at the bottom.
Tip: To reduce the file size of multiple images at the same time, Touch Bar) to rotate the image to the left. Continue clicking to keep rotating.
To rotate the image to the right, press and hold the Option key and click Use the Touch Bar on Mac