Resize images on your Mac in bulk, to 1080 px, 4K or a square crop
By Himanshu Ranjan · Updated 8 November 2026
To resize images in bulk on a Mac with FileDial, select them in Finder, hold the right Option key and choose a Resize tool, such as Resize › Resize to 1080 px, Resize › Resize to 50% or Resize › Square crop 1:1. Each image gets a resized copy beside the original. The work happens on your Mac, with no uploads.
How to do it with FileDial
- Select the images in Finder.
- Hold right ⌥ to open the dial.
- Choose Resize, then the size you need, for example Resize › Resize to 2048 px.
- Check the copies beside the originals; Undo is on the result card.
Your original file stays untouched. The result is saved beside it, and every result has Undo.
Which option to pick
| Tool | Use it when |
|---|---|
| Resize to 1080 pxResize | For social posts, chat apps and web pages where 1080 px is a common working size; new copy. |
| Resize to 2048 pxResize | When you want a larger copy that still shares easily; new copy beside the original. |
| Resize to 4KResize | For screens, slideshows or wallpapers at 4K; new copy beside the original. |
| Resize to 50%Resize | To halve dimensions whatever the starting size; new copy beside the original. |
| Square crop 1:1Resize | For profile pictures, product grids and square posts; new copy beside the original. |
Pixels, file size and choosing the right dimensions
Resizing changes the number of pixels in an image. A modern phone or camera photo has far more pixels than a website, chat app or slide will ever display, and every extra pixel adds to file size and upload time. Scaling down to the size the image will actually be shown at is the most effective way to make it lighter without visible loss.
Pick the size by where the image is going. 1080 px is a common width for social posts and many web layouts. 2048 px gives room for zooming on large screens while still sharing easily. 4K suits full-screen slideshows and displays. A percentage resize is handy when images start at different sizes and you simply want all of them smaller.
Cropping is different from resizing: it cuts part of the frame away to change the shape. A square crop is what profile pictures and many grid layouts want. Because the result is always a copy, you can try a crop and keep the full photo.
Why resize on your Mac instead of an online tool
Bulk resizing usually means a whole shoot or a product catalogue: dozens or hundreds of files to push through a website. Apart from the upload time, each photo can carry location and camera details. The FBI warned in March 2025 that free online converter sites are increasingly used to return malware-laden files and to scrape personal data, and its Denver office named ransomware as a possible outcome.
Uploaded files also have to be stored somewhere. Cybernews found in 2024 that two online PDF services had left cloud storage open, exposing 89,062 user files. Resizing in FileDial keeps every image on your Mac, and the tools work offline.
Other ways to resize images on a Mac
Preview can resize: open an image, choose Tools › Adjust Size, enter a width or height and keep Scale proportionally on. If you open several images in one Preview window and select them all in the sidebar, Adjust Size applies to the selection. On recent macOS versions, Finder's Quick Actions › Convert Image also offers small, medium and large sizes when converting.
Those routes work for occasional jobs. FileDial is quicker when you resize the same way often, when you have hundreds of photos, or when you want a chain such as Resize to 1080 px followed by Compress as a recipe or a watched folder. Originals stay put, and Undo is there for every result.
Questions
Does resizing overwrite my photos?
No. Each Resize tool saves a new copy beside the original, so your full-size photos stay as they were. The result card shows the size before and after, and Undo removes the copy.
Can I resize hundreds of images at once?
Yes. Select them all in Finder and choose one Resize tool from the dial; it runs on every selected file. In our test on a MacBook, a batch of 300 photos converted in 5 seconds.
How do I make square profile pictures?
Select the photos, hold right ⌥ and choose Resize › Square crop 1:1. You get square copies beside the originals and can keep the uncropped versions.
Can I resize and compress in one step?
Recipes chain tools, so you can build one that runs Resize to 1080 px and then Compress. Watched folders can run that recipe automatically on anything dropped into a folder.
Which Macs does FileDial run on?
FileDial needs macOS 14 (Sonoma) or later on an Apple silicon Mac with an M1 chip or newer. It has a 1-day free trial with no card or account.