Make & keep
Resize strip scans to exact pixel dimensions in Preview
Set the target width or height, preserve proportions, and use resampling deliberately.
Preview can resize one image or several images shown together in the same window. For a web or print handoff, be clear whether the requested number is pixels or a physical print size. The Resample Image setting controls whether the pixel count changes, so review the dimensions shown before saving.
Choose a pixel target
Open the scan in Preview and choose Tools > Adjust Size, or use the Adjust Size button in the Markup toolbar. Set the unit to pixels, enter the required width or height, and keep Scale Proportionally on so the strip does not stretch. With Resample Image enabled, Preview changes the pixel dimensions to the values you enter.
Evidence: Apple user guide
Apply one rule to a batch
For multiple scans, show them in one Preview window, select their thumbnails in the sidebar, and choose Tools > Adjust Size. This applies one dimension rule to the set. Check that all images share a compatible orientation and proportion; a vertical strip and a landscape image can yield different other-side dimensions under a shared proportional rule.
Evidence: Apple user guide
Verify dimensions and preserve source
If you only need to alter a print-size calculation without changing stored pixel detail, deselect Resample Image before changing physical dimensions. That changes the resolution relationship rather than inventing pixels. Save a copy under a new name, then reopen it and confirm the pixel width and height in Preview’s Inspector.
Evidence: Apple user guide
Sources & further reading
Sources for the specific facts and product descriptions above. Our worked examples, interpretations and practical suggestions are original editorial guidance.
- Apple Preview User Guide — Crop, resize or rotate imagesApple user guide