How to Resize a Photo: Every Method, Every Platform

A photo fresh from your camera is typically 4000-6000 pixels wide. That is perfect for printing a poster, but terrible for a website hero image, an email attachment, or a LinkedIn profile picture. Resizing brings the dimensions down to exactly what you need — faster load times, smaller file sizes, and no awkward cropping surprises.

This guide covers every major way to resize a photo: browser tools, desktop apps, mobile devices, and the command line. Pick the method that fits your workflow, grab the right dimensions from the reference table, and move on.

Why Photo Dimensions Matter

The pixel dimensions of a photo determine three things: how it displays, how fast it loads, and how much storage it consumes.

Web pages. A 5MB DSLR photo on a blog post forces visitors to download data they will never see — most screens display images at 1200-1600 pixels wide. Oversized images are the single biggest cause of slow page loads, and Google's Core Web Vitals penalize sites that serve them.

Social media. Every platform enforces its own dimension requirements. Upload a photo at the wrong aspect ratio and the platform crops it automatically — usually cutting off the most important part. See the dimension reference table below for exact sizes.

Print. Print resolution is measured in DPI (dots per inch), not just pixels. A photo that looks crisp on screen at 1200×800 will print blurry at anything larger than 4×2.7 inches at 300 DPI. Resizing for print means thinking in physical dimensions. Our resize for printing guide covers the DPI math in detail.

Email. Most email clients cap inline image display at 600-800 pixels wide. Anything larger gets scaled down by the client — adding load time without improving appearance. Resize before attaching.

Resize vs. Compress: Which Do You Need?

People confuse these constantly, so here is the distinction:

Often you need both. Resize first to the correct dimensions, then compress to hit your file size target. Doing it in this order minimizes quality loss — the compressor works on fewer pixels and can be less aggressive. If you only need to shrink the file size without changing dimensions, skip resizing and go straight to our compression guide.

Resize a Photo in Your Browser (Pixotter)

The fastest method if you do not want to install anything. Pixotter runs entirely in your browser — your photos never leave your device.

1. Open pixotter.com/resize/.
2. Drop your photo onto the upload area (or click to browse).
3. Enter your target width and height. Toggle the lock icon to maintain the aspect ratio (recommended — prevents distortion).
4. Click Resize.
5. Download the result. Done.

Why this is the recommended approach: No signup, no upload to a remote server, no watermarks, no file size limits. The resize happens via WebAssembly in your browser tab, so it works offline and handles even large RAW-to-web conversions in under a second. You can also convert formats and compress in the same session — one upload, everything done.

Need to resize a whole folder of product photos? Batch resize handles that too.

Resize on Windows

Photos App (Windows 11)

1. Right-click the photo → Open with → Photos.
2. Click the three-dot menu (top-right) → Resize image.
3. Choose a preset (Small, Medium, Large) or enter custom pixel dimensions.
4. Pick your output format and quality level.
5. Click Save.

The Photos app preserves EXIF data by default. It does not support batch resizing — for multiple files, use Pixotter's batch tool or Paint.

Paint (Windows 10/11)

1. Open the photo in Paint.
2. Click Resize in the Home tab (or press Ctrl+W).
3. Select Pixels, enter the new width or height. Keep Maintain aspect ratio checked.
4. Click OK, then File → Save As and choose your format.

Paint uses a basic bilinear resampling algorithm. The output is acceptable for web use but not ideal for high-quality print work. For sharper results with better algorithms, use Pixotter or the CLI tools described below.

Resize on Mac (Preview)

Preview is pre-installed on every Mac and handles resizing well.

1. Open the photo in Preview (double-click usually works).
2. Go to Tools → Adjust Size (or press ⌘+⌥+I).
3. Enter your target width or height. Make sure Scale proportionally is checked.
4. Optionally change the resolution (DPI) for print output.
5. Click OK, then File → Save (or Export to pick a different format).

Preview uses Lanczos resampling, which is one of the best algorithms for downscaling. The results are sharp and artifact-free. For batch operations, you can select multiple files in Finder, open them all in Preview, select all (⌘+A), and resize in one pass.

Resize on iPhone and Android

Both iOS and Android lack a built-in resize tool (the Photos apps crop, but do not resize to specific pixel dimensions).

iPhone: Open pixotter.com/resize/ in Safari. The web app works identically on mobile — drop or select your photo, set dimensions, download. No app install required. For cropping specifically, see our crop photos on iPhone guide.

Android: Same approach — open pixotter.com/resize/ in Chrome. The browser-based tool handles the resize locally on your device.

If you prefer a native app, both platforms have free resize utilities in their app stores, but most of them upload your photo to a remote server. Pixotter does the processing on-device.

Resize Using the Command Line

For developers and anyone processing photos in a build pipeline, CLI tools give you scriptable, repeatable resizing with fine-grained control over the resampling algorithm.

ImageMagick 7.1.x

ImageMagick is the standard image processing toolkit. Install it via your package manager:

# macOS
brew install imagemagick

# Ubuntu / Debian
sudo apt install imagemagick

# Verify version
magick --version
# ImageMagick 7.1.x

Resize to a specific width (maintain aspect ratio):

magick input.jpg -resize 1200x output.jpg

Resize to exact dimensions (may distort):

magick input.jpg -resize 1200x800! output.jpg

Resize to fit within a bounding box (no distortion, no upscaling):

magick input.jpg -resize '1200x800>' output.jpg

The > flag means "only shrink, never enlarge." This is the safest option for batch operations where source images vary in size.

Batch resize every JPG in a directory:

for f in *.jpg; do
  magick "$f" -resize 1200x -quality 85 "resized/$f"
done

Choose a resampling filter:

magick input.jpg -filter Lanczos -resize 1200x output.jpg

Lanczos produces the sharpest downscale results. For upscaling (which you should avoid when possible), Mitchell or Catrom filters produce fewer ringing artifacts.

ffmpeg 7.1

ffmpeg handles images as single-frame video. It is already installed on most developer machines:

ffmpeg -i input.jpg -vf "scale=1200:-1" output.jpg

The -1 tells ffmpeg to calculate the height automatically to preserve the aspect ratio. To force exact dimensions:

ffmpeg -i input.jpg -vf "scale=1200:800:force_original_aspect_ratio=decrease,pad=1200:800:(ow-iw)/2:(oh-ih)/2:white" output.jpg

This scales the image to fit within 1200x800 and adds white padding to fill the remaining space — useful for platforms that require exact dimensions without distortion.

ffmpeg is faster than ImageMagick for batch operations because it leverages hardware acceleration on supported systems.

Common Resize Dimensions

Bookmark this table. It covers the most common resize targets across platforms.

Social Media

For platform-specific walkthroughs, see our Facebook resize guide and LinkedIn resize guide.

Web and Email

Print

300 DPI is the standard for professional print. 150 DPI is acceptable for large-format prints viewed from a distance (posters, banners). For a deeper dive, read our resize for printing guide.

How to Resize Without Losing Quality

Every resize operation recalculates pixel data, so some quality loss is technically unavoidable. But you can make it invisible. The short version:

1. Always downscale, never upscale. Downscaling averages existing pixel data — the result is often sharper than the original at display size. Upscaling invents pixels, which produces blur or artifacts.
2. Use Lanczos resampling. Lanczos (also called Lanczos3) produces the sharpest downscale results of any standard algorithm. Pixotter and macOS Preview use Lanczos by default.
3. Resize before compressing. If you compress first and then resize, the compressor's artifacts get amplified by the resampling algorithm. Resize the uncompressed original, then compress the result.
4. Save to a lossless format if quality is critical. PNG or WebP (lossless mode) preserve every pixel exactly. Use these when you need to resize and then hand off to another tool for further editing.
5. Do not resize in multiple steps. Going from 4000px → 2000px → 1000px degrades quality more than going directly from 4000px → 1000px. Each step introduces its own interpolation artifacts.

For the full technical breakdown — including algorithm comparisons, format choices, and batch workflows — read our dedicated guide: How to Resize an Image Without Losing Quality.

FAQ

What is the difference between resizing and cropping?

Resizing changes the pixel dimensions of the entire image — every part of the photo gets scaled to the new size. Cropping cuts away the edges and keeps a portion of the image at its original resolution. Use resizing when you need a smaller version of the whole photo. Use cropping when you need to remove unwanted areas or change the aspect ratio.

Does resizing a photo reduce the file size?

Yes, significantly. A 4000×3000 photo contains 12 million pixels. Resizing to 1200×900 brings that down to 1.08 million pixels — a 91% reduction in pixel data. The file size drops proportionally. If you need to reduce file size without changing dimensions, use compression instead.

Can I resize a photo back to its original size after making it smaller?

You can increase the dimensions, but you cannot recover the lost detail. Once pixels are discarded during a downscale, they are gone. The upscaled version will look softer or blurrier than the original. Always keep the original file as your master copy.

What is the best format to save a resized photo?

For web use, WebP offers the best balance of quality and file size. JPEG works everywhere but compresses less efficiently. PNG is lossless — use it when you need transparency or zero compression artifacts. Use Pixotter's convert tool to switch formats after resizing.

How do I resize multiple photos at once?

Pixotter's batch resize tool handles folders of images in one pass. On the command line, the ImageMagick for loop shown above processes an entire directory. On Mac, select multiple files in Finder, open in Preview, select all, and use Tools → Adjust Size.

What dimensions should I use for a website header image?

1200 pixels wide covers most layouts and looks sharp on standard and retina displays. For full-width hero images on high-DPI screens, 1600-2000 pixels wide is safer. Keep the file under 200 KB after compression — anything heavier slows the page.

Will resizing remove the EXIF data from my photo?

It depends on the tool. Pixotter and macOS Preview preserve EXIF data during resize. Command-line tools like ImageMagick preserve it by default but can strip it with the -strip flag. Web-based tools vary — always check if metadata like GPS coordinates, camera model, and date are retained or removed, especially if privacy matters.

How do I resize a photo for email without it looking blurry?

Resize to 600 pixels wide (the rendering limit for most email clients), save as JPEG at 80-85% quality, and keep the file under 100 KB. Avoid PNG for email photos — the file sizes are too large for inline display. If the photo still looks blurry, the original may be too small to begin with; you cannot resize up without quality loss.