How to Change Photo Size on iPhone 15 Pro

Updated 7 November 2026 · Standard formula, shown below

This guide shows you how to resize photos directly on your iPhone 15 Pro using the built-in Photos app and the Files app, with no extra software needed. You’ll learn how to reduce a photo’s dimensions or file size, and how to convert it to a smaller format, all in a few taps.

What You’ll Need

An iPhone 15 Pro running iOS 17 or later (the steps are the same for iOS 18).
The photo you want to resize saved in your Photos library.
Enough free storage space for the new file (usually a few MB).

Step-by-Step

Open the Photos app and tap the photo you want to resize.
Tap Edit in the top-right corner.
Tap the crop/rotate icon (a square with arrows) at the bottom.
Tap the aspect ratio button (a rectangle with arrows) in the top-right of the crop tools.
Choose a preset aspect ratio like Original, Square, or 16:9. This changes the shape, not the pixel size directly, but it’s the first step if you want a specific ratio.
To actually reduce the pixel dimensions, you need to use the Files app. First, go back to the photo and tap Share (the square with an up arrow) at the bottom-left.
Scroll down and tap Save to Files. Choose a location like On My iPhone, then tap Save.
Open the Files app and navigate to where you saved the photo.
Tap and hold the photo file until a menu appears, then tap Quick Actions > Convert Image.
In the Convert Image screen, you can change the Format (e.g., JPEG) and reduce the Size slider. Drag the slider left to make the image smaller (e.g., 50% reduces both dimensions by half).
Tap Save in the top-right. The resized copy will be saved in the same folder with “-converted” in the name.
If you need a specific pixel size (like 1200×800), use the Shortcuts app: create a new shortcut, add the Resize Image action, set the width/height, and run it on your photo.

Common Mistakes

Using Edit to crop only: The Edit tool changes the composition, not the file size or pixel count. It doesn’t actually shrink the image for sharing.
Emailing the original: When you share a photo via Mail, iOS gives you options like “Small,” “Medium,” or “Large” – but if you choose “Actual Size,” you’re sending the full-resolution original.
Forgetting to save a copy: Convert Image creates a new file; it doesn’t overwrite the original. If you want to replace the original, you’ll need to delete it manually.
Ignoring the file size: Changing dimensions to 50% doesn’t always reduce file size by 75% – it depends on the image content and format.

Tips

For sharing on social media, a 50% reduction is usually enough – most platforms compress images anyway.
If you need a specific file size (like under 2MB), use the Shortcuts app with the Resize Image action and then check the file size in Files.
Use JPEG format for photos with lots of colors; it gives smaller files than PNG for typical photos.
Keep the original photo backed up in iCloud or on your computer before deleting the full-resolution version.

Troubleshooting

“Convert Image” doesn’t appear in Quick Actions. Make sure the file is saved as an image (HEIC, JPEG, PNG). If it’s a Live Photo, it may be saved as a video – use the Shortcuts method instead. Also, check that you’re using a recent iOS version.

The resized image looks blurry. You may have reduced the size too much. Try a 70-80% reduction instead of 50%. Also, avoid upscaling – if you increase the size, it will look pixelated.

I can’t find the converted file. It’s saved in the same folder as the original, with “-converted” appended to the filename. If you don’t see it, try searching in Files using the name.

Shortcuts app won’t run the Resize Image action. Make sure you’ve granted the Shortcuts app permission to access your photos. Go to Settings > Privacy > Photos and ensure Shortcuts has “Read and Write” access.

Frequently Asked Questions

Does changing the photo size on my iPhone reduce the quality?

Yes, reducing the pixel dimensions or file size will lower the image quality, but if you’re just sharing on social media or email, the difference is often unnoticeable. For printing, keep the original size.

Can I set a specific pixel size like 1920×1080?

Yes, use the Shortcuts app. Create a shortcut with the “Resize Image” action, set the width and height manually, then run it on any photo.

Will the resized photo replace the original?

No, the Convert Image feature saves a new copy. The original stays untouched in your Photos library. You can delete the original later if you want.

What’s the best format for a smaller file size?

For most photos, JPEG gives the smallest file size at a given quality. HEIC is even smaller but may not be supported by all websites or apps. PNG is best for graphics with text or transparent backgrounds.

Why does my photo still look huge after I resized it?

You may have only changed the aspect ratio in Edit, which doesn’t change the pixel count. Use the Convert Image method to actually reduce dimensions.

Can I resize multiple photos at once?

Yes, in the Files app, select multiple images, then use Quick Actions > Convert Image. You’ll get a single converted file for each, but they’ll all be saved at once.

Method: the standard formula for this calculation, rounded as each result states. See how the calculators work or report an error.