How to Reduce Photo File Size on iPhone: The Fast Way and the Built-In Way

The fast way: tell Mochify the size you need

The quickest way to get an iPhone photo under a size limit is to say the limit out loud, so to speak. Mochify's Magic Flow takes a plain-English instruction such as "compress to 1MB", works out how to get there, and hands back the file. A language model reads your instruction, then our C++ engine does the encoding, so there is no slider to fiddle with and no estimate to watch.

On our test photo (a 4.3MB, 24 MP JPEG straight from the camera), "compress to 1MB" came back with the reply "Compressing your image to come in under 1MB while preserving its full dimensions", and the download was 964KB at the original 4284 x 5712. The same job in Preview took ten-odd taps across Photos and Preview, and on iOS 26 a hunt for a menu arrow that was nearly invisible in dark mode.

Make it one tap next time. In Safari, open mochify.app/flow, tap Share, then Add to Home Screen. It sits on your Home Screen like an app, so shrinking a photo becomes: tap the icon, pick the photo, type the size.

It does more than shrink. The same box takes any instruction Magic Flow understands, for example:

• "resize to 2048 pixels on the long side and convert to JPG"
• "convert to JPG and crop to a square"
• "remove the background and put it on a white background"

JPEG output goes through Google's jpegli encoder, so you get a standard JPG that opens everywhere with fewer wasted bytes at the same quality. If all you need is a straight HEIC-to-JPG conversion with nothing to set, the HEIC to JPG converter does exactly that, though conversion alone often does not make a photo smaller.

Location data is stripped by default. Our 964KB download carried no EXIF data at all, so no GPS coordinates and no camera details. Preview does the opposite: its export keeps the lot, including where the photo was taken. Our guide to EXIF risks explains what a photo gives away.

Limits worth knowing. Without an account you get 3 images a month; a free account gets 25 a month, up to 20MB per file and 3 photos per batch. For a one-off pile of photos, a Day Pass is $2 for 100 uploads within 24 hours, up to 75MB each and 25 at a time, with no subscription. Camera RAW files, including iPhone ProRAW .DNG, are not accepted; edit or share a RAW shot as a JPG first. Plans and limits are on the pricing page.

Compress your iPhone photo now.

Mochify workflow: compress an iPhone photo to a set size

Mochify or Preview: side by side

Both routes get a photo under a limit; they differ in effort, control and where the photo goes. We ran the same 4.3MB, 24 MP photo through each, on iOS 26.7 and again on iOS 27.

When the built-in way is the better choice: you would rather the photo never leaves your phone, you need to keep its location data, or you are shrinking more photos a month than the free allowance covers and do not want a plan. For everything else, the fast way is faster.

Why iPhone photos are so big now

iPhone photos are big because recent iPhones shoot more pixels by default, and some shooting modes multiply the file size on top of that. On supported models the Main camera saves 24 MP photos by default, and Resolution Control or ProRAW can push that to 48 MP, according to Apple's camera settings guide.

A 24 MP frame is 5712 x 4284 pixels, just over 24.4 million of them. That is twice the pixel count of the 12 MP photos iPhones took for years. The HEIC format keeps those files reasonably small on the phone, but the moment a website, a form or a Windows PC wants something else, you are dealing with a lot of image.

RAW is the extreme case. Apple's ProRAW documentation puts a ProRAW file at about 25MB at 12 MP and about 75MB at 48 MP, and says ProRAW files are 10 to 12 times larger than HEIF or JPEG. If you turned RAW on for one shot and forgot about it, that alone explains an upload form's complaint.

Three things usually push a photo over a limit:

• Resolution. 24 MP or 48 MP where the destination would be perfectly happy with a fraction of that.
• Format. The form wants JPEG, and a straight HEIC-to-JPEG conversion often comes out larger than the HEIC, because HEIF compresses better at the same visual quality (Apple's HEIF and HEVC notes).
• Shooting mode. RAW, and the 48 MP modes, produce files several times the size of a standard shot.

File size or dimensions: which one is your problem?

Check what the upload form is actually asking for before you shrink anything, because "too large" means two different things. File size is the megabytes on disk ("must be under 2MB"). Dimensions are the pixel width and height ("at least 600 x 600", "no larger than 2000 pixels"). Many forms state both.

They are connected but not the same. Cutting the dimensions in half removes three quarters of the pixels, which usually brings the file size down sharply. Lowering JPEG quality reduces the megabytes without touching the dimensions at all. Cropping does both, but only by throwing away part of the picture.

A quick rule for choosing:

• The form names a megabyte limit and nothing else: lower the export quality first. If you have to drag the slider a long way and the photo starts to look smeary, reduce the dimensions instead.
• The form names a maximum pixel size: resize to that size. The file size will usually follow.
• The form rejects the file with no clear reason: it may be the format, not the size. Many sites still do not accept HEIC (our guide to Safari and HEIC on the web covers why), so export as JPEG either way.

To see where you stand, open the photo in Preview and tap the small arrow beside the filename at the top of the screen: the menu shows the file's format and size.

The built-in way: Preview on iOS 26 and later

Preview is the built-in answer to the old complaint that the iPhone has no native way to resize or compress a photo. Apple brought its Preview app to iPhone with iOS 26, and it does both: Export re-saves an image as HEIC or JPEG with a Size slider and a live file-size estimate, and Adjust Size changes the pixel dimensions. Most of the pages ranking for this question were written before it existed, and the few that mention it leave out the estimate, which is the part that makes it useful.

We tested every step below on an iPhone running iOS 26.7, then again after updating to iOS 27, with a 24 MP photo straight from the camera: 4284 x 5712 pixels, 4.3MB. The results were identical on both.

Step 1: get the photo into Preview

Preview opens files from the Files app's locations (Recents, Shared and Browse), not straight from your Photos library. Two ways in:

• From Photos: open the photo and tap Share. Preview was not in the row of apps on our phone: scroll the row to the end, tap More, and you will find Preview near the bottom of the list. Tap Edit on that screen to add it to the row for next time.
• Via Files: in Photos, tap Share, then Save to Files and pick a folder. Open Preview, tap Browse, and open the saved copy.

Sharing a photo to Preview saves a copy into a Preview folder in the Files app straight away. Your original stays in the Photos library untouched.

Step 2: export as JPEG and watch the estimate

This is the step that sets the file size. Following Apple's Preview export instructions:

1. Tap the small arrow to the right of the filename at the top of the screen. On iOS 26 it is easy to miss, because in dark mode the filename is close to invisible and the arrow is tiny; iOS 27 shows the filename clearly. The menu shows the file's format and current size, then Duplicate, Move, Rename, Export and Print.
2. Tap Export and choose JPEG under Format. On iOS 27 it starts on HEIC, which is smaller but rejected by plenty of forms.
3. Drag the Size slider in the Options box. It moves in steps (about ten), and the Estimate file size figure under Format updates at each one. Stop when it is under your limit.
4. Tap the tick at the top right, choose where to save (it offers the Preview folder by default), and save.

What that looked like on our 4.3MB test photo, with the dimensions left at 4284 x 5712:

Two things stand out. The default setting produces a file larger than the original, because the slider starts near maximum quality, so exporting without touching the slider can make things worse. And the slider alone took a full-resolution 24 MP photo from 4.3MB to 993KB, 77% smaller, without resizing at all. The exported file came out at exactly the estimated 993KB.

Step 3 (if it looks rough): reduce the dimensions with Adjust Size

If you have to drag the slider a long way and the photo starts to show blocky edges or banding in the sky, cut the dimensions instead. Tap the three-dot menu at the top right, then Adjust Size (Apple: edit an image in Preview on iPhone):

• Switch the width and height units to pixels (our phone defaulted to inches; percent, centimeters and millimeters are also offered).
• Leave Scale Proportionally and Resample Image on (both are on by default). With Resample Image off, the proportions setting is grayed out.
• Enter 2048 for the long side. The other side follows: our portrait photo became 2048 x 1536.

Preview saves the resized image as a new file alongside the copy you shared, so nothing is overwritten. Then export it as in Step 2. Resized to 2048 x 1536, our test photo estimated 857KB at the default slider position, 1.9MB at full quality and 160KB at the lowest. At that size you can keep the quality high and still land under most limits.

What Preview keeps: location included

Preview's export keeps the photo's metadata, including where it was taken. On our 993KB export, Preview's Info panel (the "i" button at the bottom right, beside Share) listed the latitude and longitude along with full Exif, GPS, IPTC and TIFF data. If you are posting the photo publicly, that matters.

You can save the exported file back into Photos (share it to Photos from Files; Preview asks once for permission). In our test the copy in Photos showed no camera details, offered to add a location, was labeled "Saved from Preview" and got a new IMG number. Do not treat that as a privacy step: the file in Files still carried its location, and what a website receives depends on which copy you upload. Mochify strips location by default, as covered above.

Other built-in routes: Files, Shortcuts and Mail

Preview gives you the most control, but the Files app and Shortcuts can shrink a photo too, each with a catch. Mail, which older articles recommend, did not offer a smaller size in our test.

The Files app: Convert Image

The Files app converts an image to a preset size in a few taps. Long-press the image in Files, choose Quick Actions, then Convert Image, and pick a file format (JPEG, PNG or HEIF) and an image size: Small, Medium, Large or Original. We confirmed those options on iOS 26.7 and iOS 27. Files writes a new file next to the original.

It is quicker than Preview when a preset is good enough, but there is no live estimate, no way to set an exact width, and Apple does not publish the pixel sizes behind each preset.

Shortcuts: resize a batch

Shortcuts is the built-in route for more than one photo at a time. In Apple's Shortcuts app, a shortcut with a Resize Image action followed by Convert Image (set to JPEG) takes whatever photos you share to it, scales each one to the width you set, and hands back JPEGs. Convert Image has a quality setting and an option to leave out metadata such as location. We confirmed both actions in the Shortcuts app on iOS 26.7.

Building it takes five minutes once. After that it sits in the Share sheet and handles twenty photos as easily as one, which none of the other built-in routes do.

Mail: do not count on it

The most-upvoted answer on the top-ranking Apple Community thread, from 2018, says to email the photo to yourself and pick a smaller size when Mail asks. In our tests on iOS 26.7 and iOS 27, sharing a photo to Mail offered no size choice at all, so we do not recommend it as a route. Mail does still shrink one kind of photo for you: Apple says that when you add a ProRAW photo to a message, "the Mail app converts the ProRAW file to a smaller JPG file automatically" (Apple ProRAW support).

What does not work (or not the way you think)

Several popular tips either do not reduce the file you send, or do it by damaging the photo. Four to skip:

• Switching the camera to Most Compatible. This makes new photos JPEG instead of HEIF, and Apple is explicit that HEIF uses less storage "while preserving the same visual quality." Most Compatible makes photos more compatible and larger. At least one ranking article recommends it for smaller files; it has it backwards.
• Turning on Optimize iPhone Storage. This is a storage setting for iCloud Photos: it keeps space-saving versions on the phone while the full-resolution originals live in iCloud. It frees space on your phone. It does not give you a smaller copy to send, so it is the wrong tool for an upload limit.
• Taking a screenshot of the photo. It does produce a smaller file, but at whatever resolution your screen happens to be, with any on-screen clutter cropped out by hand. You lose detail you cannot get back and have no control over the result. Preview's Adjust Size does the same job properly.
• Cropping as a compression method. Cropping reduces the file because it discards part of the picture. If you want the whole picture, resize instead.

Stop the problem at capture: camera settings

If you regularly send photos to forms or listings, change how the camera saves them rather than shrinking every file afterwards. Three settings matter, all under Settings > Camera > Formats.

• Photo Mode: 12 MP or 24 MP. On supported models you can drop the default from 24 MP to 12 MP under Settings > Camera > Formats > Photo Mode (Apple). A 12 MP photo has half the pixels of a 24 MP one: 12.2 million against 24.5 million. You give up cropping headroom; for listing photos and forms, you will rarely miss it.
• Resolution Control and ProRAW. Leave these off unless you need 48 MP or RAW for editing. If you do shoot RAW, remember that each file runs to tens of megabytes.
• High Efficiency, not Most Compatible. HEIF keeps files smaller on the phone. Convert to JPEG at the moment you need a JPEG, not at capture.

Changing Photo Mode only affects new photos. Everything already in your library stays the size it is.

Getting under an upload limit: what to aim for

Aim for the destination's stated limit with some headroom, and compress before you resize, because compression keeps every pixel. Upload forms, job portals and government sites usually state a maximum in megabytes, and occasionally a pixel range. Where they do not, a JPEG around 2048 pixels on the long side is a safe default: sharp on any screen, and a fraction of the original's pixels.

A practical order of operations:

1. Set the size. Tell Mochify "compress to 2MB" (or whatever the limit is), or export as JPEG from Preview and drag the Size slider until the estimate is under the limit, with some headroom.
2. Look at the result. If it is sharp, you are done.
3. If it looks rough, bring the long side down to 2048 pixels (or what the destination asks for) and compress again: "resize to 2048 pixels on the long side" in Mochify, or Adjust Size in Preview.
4. If it is still over, resize again (to 1600 or 1200 pixels) rather than crushing the quality.

This matters because the two levers do different damage. Lower dimensions make a photo smaller everywhere. Lower quality leaves it the same size on screen with blocky edges and banding in skies, which is what people actually notice. Our guide to why free tools reject large camera files covers the same problem from the camera side, and should you optimize images before uploading explains why shrinking before upload beats letting the site do it.

If you are sending the photos as a document rather than as images, converting iPhone photos to PDF is often what the form really wants.

Cheat sheet: which route to use

Rule of thumb: name the size you need and compress first; if the photo looks rough at that size, resize to 2048 pixels on the long side and compress again.

FAQ