Why are my iPhone photos so big?

Your first guess is usually the format. Since iOS 11, iPhones default to High Efficiency, which saves HEIC. HEIC is typically smaller than the equivalent JPG. Switching Camera → Formats to Most Compatible saves JPG instead and makes files larger, not smaller.

The main reason your files are big is resolution. A 12MP still already holds a lot of pixels. iPhone 14 Pro and later models with 48MP sensors capture far more. More pixels mean more data even when the file is HEIC.

Two extras add bulk on top of pixels:

• Live Photos attach a short video clip and add a few MB per shot.
• ProRAW (DNG) on Pro models is much larger — tens of megabytes — because it stores minimally processed sensor data.

On the iPhone, change how new photos are captured:

• Open Settings → Camera → Formats. Keep High Efficiency (HEIC) unless you need JPG for a specific app. Most Compatible makes files larger.
• Turn off Live Photos in Camera if you do not need motion. That short video clip adds a few MB every time.
• Leave 48MP capture and ProRAW off unless you need the extra detail or a DNG for editing.

Those switches only affect photos you take from now on. They do not shrink the camera roll you already have. For files already shot, use the browser steps next.

EditItAll is a browser tool, not an iPhone app. Open the HEIC compressor in Safari on your iPhone or on a computer, drop in one or more photos, and export a smaller copy.

You pick a quality level and an optional max-dimension cap. Size is an output you read after export, not a number you type in. There is no field for a target size such as 100 KB. Check the in → out size on each result, then lower quality or dimensions if you still need it smaller.

Everything runs in your browser. Photos are never uploaded, and you can go offline after the page loads. Batch several at once and download a ZIP. Export also strips EXIF and GPS, so location data does not ride along. The same compression tools handle JPG if you already converted. If the huge file is ProRAW (DNG), convert it with DNG to JPG instead of treating it as HEIC.

Many Windows apps and upload forms reject HEIC. That is why people convert to JPG. Converting HEIC to JPG re-encodes once, and the JPG is often larger than the original HEIC.

If a form will not take HEIC, use the HEIC to JPG converter. You pick quality; EXIF and GPS are stripped. The steps are in convert HEIC to JPG without uploading.

If the problem is size, stay in HEIC and compress it. Quality versus size is covered in compressing images without losing quality. For attachments, see reducing image file size for email. Related guides live under compressing images.