Why resize a HEIC photo?
Modern iPhone photos are far bigger than most uses need. A 48-megapixel shot is roughly 8000 pixels wide, which is glorious for printing and absurd for a profile picture.
Resizing solves the dimension problem. Converting solves the file-size problem. They are not the same thing, and picking the wrong one wastes your time.
Resizing changes how many pixels an image has. Converting changes how those pixels are stored. If a website rejected your photo for being too large, read the error carefully — it may mean either.
Common reasons to resize
Upload limits with pixel caps
Some forms reject images above a certain width or height rather than a file size. Job applications, government portals and older forums all do this.
Web pages
Serving an 8000px photo to a 400px slot wastes bandwidth on every visit. Resize once, benefit forever.
Email and messaging
A resized photo sends faster and is more likely to survive an attachment limit.
Consistent sets
Product listings, documentation and galleries look better when every image shares dimensions.
How to resize a HEIC file
The tool above offers four ways to specify a size. They exist because people think about this differently.
Longest edge
You give one number and the image fits inside it, whichever way it is oriented.
This is the most useful mode for a mixed batch of portrait and landscape shots, because they all end up consistently sized without you sorting them first.
Exact width, or exact height
You set one dimension and the other follows the aspect ratio.
Use width when your target is a page column. Use height when your target is a row of images that must line up.
Percentage
You scale by a proportion instead of a number. Half size, quarter size.
Handy when the originals vary in size and you want to preserve that variation.
Setting both width and height
Possible, but be careful: if the ratio does not match the original, the image is squeezed. Leave one field empty unless you genuinely want that.
Resizing does not preserve the HEIC format
Worth being direct, because it affects what you get back.
No browser can write a HEIC file. The format’s HEVC compression is patent-encumbered, and no browser vendor has licensed an encoder for it.
So a resized HEIC comes back as JPG, PNG or WebP — you pick which. This is a genuine limitation of doing the work on your own device rather than a shortcut, and the alternative is uploading your photos to somebody’s server.
💡 Pro tip: JPG for sharing and email, PNG when you need lossless or transparency, WebP when the image is going on a website.
📖 Further reading: why browsers can read HEIC but not write it covers the licensing in full.
What size should you actually pick?
“Resize it smaller” is easy to say and hard to act on without a number. These are sensible defaults rather than rules.
| Where it’s going | Longest edge | Why |
|---|---|---|
| Email or messaging | 1920 px | Sharp on any screen, sends quickly |
| A website or blog post | 1280 px | More than most layouts ever display |
| Social media upload | 2048 px | Platforms re-compress anyway; this survives it |
| Profile picture or avatar | 512 px | Displayed small, often cropped square |
| Attaching to a form | 1600 px | Comfortably under most pixel caps |
| Printing at 6×4 inches | Keep original | Print needs every pixel you have |
A rule of thumb for screens
A photo only needs about twice the pixels of the space it will be displayed in. Beyond that, the extra detail is thrown away by the screen.
Twice, rather than exactly, because high-density displays pack more physical pixels into the same area.
When to keep the original size
Anything destined for print, archiving, or further editing should stay full size. Resize a copy and keep the original.
Printing at 300 DPI needs roughly 1800 pixels for a 6-inch print. A modern iPhone photo has far more than that, which is exactly why it is worth keeping.
Resize or convert — which do you need?
This is the single most common mix-up, so here it is plainly:
| What you want | What to use |
|---|---|
| Fewer pixels | This resizer |
| A smaller file at full resolution | HEIC to JPG |
| Lossless copy, same size | HEIC to PNG |
| A web-ready image | HEIC to WebP |
| Several photos in one document | HEIC to PDF |
| Just to look at it | HEIC viewer |
If a service told you the file was “too large”, check whether it meant megabytes or pixels. For megabytes, converting to JPG at quality 85 usually solves it without touching the dimensions at all.
What resizing costs you
Downscaling is permanent
The discarded pixels are gone. Keep your originals if the photo matters — resize a copy.
Upscaling cannot add detail
Enlarging an image stretches the pixels you already have. It never recovers detail the camera did not capture, whatever an “AI upscale” claims to do.
Repeated resizing compounds
Each pass through a lossy format costs a little quality. Resizing an image you already resized, then resizing that again, adds up in a way a single step does not.
Go back to the original each time rather than working from the last output. It costs nothing and avoids the problem entirely.
Metadata is not carried over
The resized image is re-encoded from raw pixels, so EXIF data including GPS coordinates does not travel with it.
For most people that is a bonus. If you needed the capture data preserved, note it first — the HEIC EXIF viewer shows what the original holds.