
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. 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.įorce 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. Įnter new values for width and height, or click the “Fit into” pop-up menu and choose a size. If the Markup toolbar isn’t showing, click the Show Markup Toolbar button, then click the Adjust Size button. You can also reduce the file size to save disk space or download an image more quickly. You can resize or rotate an image opened in Preview to fit into a particular spot. You can also check out this article on how to resize an image: Resize, rotate, or flip an image

If different sizes are available, you can choose one from the pop-up menu located on the right side of the message header.

Some images may not have the option to resize: Add attachmentsīy default, Mail inserts images at their actual size. I would check to see if you're able to use this feature with another image. It's my understanding that you're unable to resize an image in the Mail app when composing an email.
