OmniImage
OMNIIMAGE GUIDE
How to Batch Resize Mixed Image Sizes on Mac
Resize landscape, portrait, and square images together while preserving each image's aspect ratio.
To batch resize images with different dimensions on Mac, open Resize in OmniImage, add the mixed images, and choose one rule: percentage scale, longest edge, width, or height. OmniImage calculates each output independently and preserves its aspect ratio, so the batch does not become distorted.
STEP BY STEP
- 1
Add the mixed images
Landscape, portrait, and square images can be selected together. Their original dimensions do not need to match.
- 2
Choose one sizing rule
Use percentage for proportional reduction, longest edge for a shared maximum, or width or height when one dimension must be consistent.
- 3
Review calculated sizes
Check the output dimensions before processing. Each file receives its own calculated companion dimension to preserve proportion.
- 4
Process the batch
Choose an output folder and create the resized copies. Originals remain unchanged and can be used again for another target.
Choose the right approach
Percentage
Best when every image should become, for example, half of its own original size.
Longest edge
Best for mixed orientations that must fit within a common maximum dimension.
Width or height
Best when a layout requires one consistent dimension and varying companion dimensions are acceptable.
A shared rule is better than one forced width and height
Forcing every image into the same width and height stretches some images unless their original aspect ratios already match.
If every output must have the exact same rectangle, use Batch Crop first or choose a shared aspect ratio, then resize the cropped results.
Common questions
What happens to portrait images when longest edge is selected?
Their height usually becomes the target longest edge, while width is calculated proportionally. Landscape images typically use the target as width.
Can resize and crop solve the same problem?
No. Resize changes dimensions without removing content; crop removes edge content to reach a target aspect ratio.