PDF files may contain many images. Removing the images from a PDF file is usually not an option since they are necessary for many PDFs. Downsampling the images will decrease the number of pixels and is possibly the most effective way to reduce PDF file size. The user can control the PDF file size with respect to the quality of the image.
Preview User Guide
Preview User Guide
- The Adjust Size / Colour feature in Preview doesn't work for PDF files, only for bitmap image files. Usually you don't want to change the format of a PDF document, anyway. However, if you have a PDF file that contains only embedded bitmap images, and you want a downsized version of that image, it's possible to use the Preview's export feature.
- Follow the steps to Reduce PDF File Size on Mac with Preview. Open your PDF file in Preview, generally speaking, it is the default PDF viewer on your mac. Then you should go to menu bar on the top, click 'File', and select 'Export' at the drop-down list, a window will pop up guiding you to reduce PDF file size on mac.
- You can reduce the size of a Portable Document Format file on a Mac by using the built-in Preview program's Reduce File Size function. You can also use third-party tools on a Mac to reduce PDF size. Reduce PDF Size With Preview Preview, the OS X utility, provides a mode to reduce a PDF's file size.
You can resize or rotate an image opened in Preview to fit into a particular spot. You can also reduce the file size to save disk space or to download an image more quickly.
Change an image's dimensions
In the Preview app on your Mac, click the Show Markup Toolbar button (if the Markup toolbar isn't showing), then click the Adjust Size button .
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, display the images in the same window, select them in that window's sidebar, then choose Tools > Adjust Size.
Rotate or flip an image
In the Preview app on your Mac, open the file you want to change.
Do any of the following:
Rotate an image: Select the image, then click (or use the 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 until you're done rotating the image.
Flip an image: Choose Tools > Flip Horizontal or Flip Vertical.
Tip: To rotate or flip multiple images at the same time, display the images in the same window, choose View > Thumbnails, select them in that window's sidebar, then choose Tools > [Rotate or Flip].
Reduce an image's file size
In the Preview app 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.
Mac Preview Reduce Pdf Size
Tip: To reduce the file size of multiple images at the same time, display the images in the same window, select them in that window's sidebar, then choose Tools > Adjust Size.
Reduce Pdf File Size Using Preview File
