Before you start
- The images to resize
Method 1 Windows: PowerToys Image Resizer
By default it creates copies with “(Medium)” etc. in the name, keeping your originals.
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Step 1: Install PowerToys
Install Microsoft PowerToys from the Microsoft Store and make sure Image Resizer is enabled.
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Step 2: Select images
In File Explorer, select the images.
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Step 3: Resize
Right-click > Resize with Image Resizer (Windows 11: may be under Show more options). Choose a preset (Small, Medium, Large) or custom size, and click Resize.
Method 2 Mac: Preview
Preview overwrites the files, so work on copies.
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Step 1: Open together
Select the images in Finder and open them with Preview.
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Step 2: Select all
In the sidebar, click one thumbnail and press Cmd + A.
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Step 3: Adjust size
Choose Tools > Adjust Size, set width or height (keep Scale proportionally ticked) and click OK. Then File > Save.
Method 3 iPhone: Shortcuts
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Step 1: Create a shortcut
In Shortcuts, add actions: Select Photos (allow multiple) > Resize Image (e.g. width 1200) > Save to Photo Album.
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Step 2: Run it
Run the shortcut and select your photos.
Troubleshooting
Image Resizer isn’t in the right-click menu
Open PowerToys settings and enable Image Resizer; restart File Explorer.
Frequently asked questions
What size should images be for the web?
Around 1200–2000 pixels on the longest side is plenty for most websites and email.
Does resizing reduce quality?
Making images smaller is fine; enlarging them reduces sharpness.
Summary
Use PowerToys Image Resizer on Windows, Preview > Tools > Adjust Size on Mac, or a Shortcut on iPhone to resize many images at once, keeping your originals safe.
