How to reduce an image's file size (5 ways)

The 5 ways to make a picture smaller

Every method below works on one of five levers. Knowing which one you are pulling makes it much easier to hit a size limit without ruining the image.

1. Resize: reduce the width and height in pixels. This usually saves the most, because a smaller picture has fewer pixels to store.
2. Compress: lower the quality setting of a JPG, WebP or AVIF so the encoder discards detail you are unlikely to notice.
3. Compress to a target: let a tool search for the highest quality that fits a limit such as 100 KB or 500 KB.
4. Change format: a photo saved as PNG, BMP or TIFF is often far bigger than the same photo as JPG, WebP or AVIF.
5. Strip metadata: removing EXIF, GPS and embedded previews saves a little space and protects your privacy.

On Windows: Photos or Paint

Windows 11 includes two free options. The Photos app can resize and save a copy with a quality setting, while Paint lets you type exact pixel values. Menu names vary between Windows versions and app updates.

1. Photos: open the image, select the three-dot See more menu and choose Resize image.
2. Pick one of the preset sizes, or choose to define custom dimensions with Maintain aspect ratio switched on.
3. If a quality slider is shown, lower it a little (around 80 to 85 for photos), then save the resized copy under a new name.
4. Paint: open the image and choose Resize (or press Ctrl+W). Select Pixels, keep Maintain aspect ratio ticked and enter a new width.
5. In Paint, choose File > Save as > JPEG picture. Paint does not offer a quality slider, so resizing is your main control there.

On a Mac: Preview or Finder

Preview gives you both levers in one place and even estimates the resulting file size before you save. Finder can batch-convert several images at once.

1. Open the image in Preview and choose Tools > Adjust Size. Select pixels, keep Scale proportionally checked and type a new width or height.
2. Choose File > Export. Set Format to JPEG (or HEIC) and drag the Quality slider; Preview shows an estimated file size underneath.
3. Save the copy with a new name so your original stays untouched.
4. For several photos at once, select them in Finder, right-click and choose Quick Actions > Convert Image. Pick JPEG and an image size such as Medium.

On iPhone and Android

Phones do not make resizing obvious, but there are a few routes. Settings and menu names change between iOS versions and Android manufacturers, so treat these as pointers rather than exact paths.

1. iPhone, for future photos: Settings > Camera > Formats > High Efficiency stores new photos as HEIC, which is roughly half the size of a comparable JPG.
2. iPhone, for a single message: when you send photos with the Mail app, it can offer smaller size options such as Small, Medium or Large before the message goes out.
3. iPhone, for repeat jobs: the Shortcuts app has Resize Image and Convert Image actions you can chain into a shortcut that runs from the share sheet.
4. Android: many gallery apps, Samsung Gallery among them, include a Resize option in the edit or more-options menu. Google Photos has no simple resize button, so a browser tool is often quicker.
5. Any phone: open ConvitAll in your mobile browser and use the image compressor directly; the photos are processed on the phone itself.

Online and private: compress to a KB target with ConvitAll

Many online compressors upload your photo to a server. ConvitAll does the work inside your browser instead, so the image never leaves your device. It handles up to 20 images per batch, there is no sign-up and no watermark.

1. Open the image compressor and add your photos. JPG, PNG, HEIC, WebP, AVIF and TIFF inputs all work.
2. Choose JPG, WebP or AVIF output and enter your limit under Maximum KB per image, for example 100, 200 or 500.
3. Under Image size, pick a longest side that suits the limit: about 800 px for 100 KB or less, about 1,280 px for 200 to 300 KB.
4. Convert. The tool tries up to eight quality levels per image, then tells you whether each one fits and which quality it used.
5. If a result is still over the limit, choose a smaller Image size and convert again from the original. Download each file or the whole batch as a ZIP.

MB vs KB vs pixels

Pixels describe how large an image is on screen, for example 4,032 × 3,024, which is about 12 megapixels. Megabytes and kilobytes describe how much storage the file needs. The two are linked, since more pixels need more data, but the format and quality setting make a huge difference too, so two images with identical dimensions can differ in size by ten times or more.

For units: 1 MB is 1,000 KB, and 1 KB is 1,000 bytes in ConvitAll, as on macOS. Windows File Explorer counts 1 KB as 1,024 bytes and therefore shows slightly smaller numbers for the same file. When an upload form is strict, aim a few percent under its limit. The table below gives rough, typical sizes to help you choose settings; your own results depend heavily on the content of each photo.

Why did my image get bigger?

Converting a JPG or HEIC photo to PNG almost always increases its size, sometimes by several times. PNG is lossless, so it has to store every subtle variation in a photo exactly, whereas JPG and HEIC discard detail you are unlikely to see. BMP and TIFF output are uncompressed and grow even more.

A high quality setting can also produce a file larger than the original if the original was already compressed hard. Re-saving does not bring back lost detail, it just spends more bytes describing the same picture. Start each attempt from your original file rather than compressing an already compressed copy, and choose a lossy format for photos.

Keep your original

Resizing and lossy compression permanently remove information from the copy you create. Always save the smaller version under a new name, check faces, text and edges at full size before you send it, and keep the original for printing or future edits.