Image Resizer - Resize Images by Pixels or Percentage Free

Resize any image in seconds — no upload, no account needed

Drop your image, type the dimensions you want, and download. The image resizer above handles JPEGs, PNGs, and WebPs right in your browser — your file never leaves your device.

How to resize an image

1. Drop or select your image — click the upload area or drag a file straight from your desktop.
2. Choose a resize mode — pick Pixels to set exact width/height, or Percentage to scale by a fraction (e.g. 50% = half size).
3. Enter your target size — the aspect-ratio lock (the chain icon) keeps your image from stretching. Turn it off only when you need a non-proportional crop.
4. Hit Resize and preview the result instantly.
5. Download your resized image in the format you need (JPEG, PNG, or WebP).

Worked example: shrinking a photo for email or social

Say you have a camera photo that is 4032 × 3024 px and 5 MB — too big to attach to an email or post on most platforms.

Type 1200 in the width field with the aspect-ratio lock on. The height updates to 900 automatically. Click Resize, then save as JPEG. Done — a clean 1200-wide photo, ready to share.

How to resize an image in code

Need to automate bulk resizing or do it server-side? Here are minimal, copy-pasteable snippets for the two most common languages.

Python (Pillow library)

# pip install Pillow
from PIL import Image

img = Image.open('photo.jpg')
resized = img.resize((1200, 900), Image.LANCZOS)  # width, height in pixels
resized.save('photo_resized.jpg', quality=85)

Image.LANCZOS is a high-quality downscaling filter — use it whenever you are making an image smaller. For percentage-based scaling, multiply img.size by your factor before passing it to resize().

JavaScript (browser Canvas API)

// Runs in any modern browser — no library needed
function resizeImage(file, targetWidth) {
  const img = new Image();
  img.onload = () => {
    const scale = targetWidth / img.naturalWidth;
    const canvas = document.createElement('canvas');
    canvas.width = targetWidth;
    canvas.height = Math.round(img.naturalHeight * scale);
    canvas.getContext('2d').drawImage(img, 0, 0, canvas.width, canvas.height);
    const url = canvas.toDataURL('image/jpeg', 0.85);
    console.log('Resized data URL ready:', url.slice(0, 60));
  };
  img.src = URL.createObjectURL(file);
}

This is essentially what the tool above does under the hood — draw the source image into an off-screen canvas at the new size, then export it. The MDN docs on Canvas API cover every option in detail.

How it works

When you resize an image here, your browser reads the file into memory, draws it onto an invisible HTML canvas at the new width and height you specified, and exports the result as a new image file. No server is involved at any point — the resize computation is done entirely by your browser's own graphics engine.

For downscaling (making an image smaller), the algorithm averages nearby pixels together, so the result looks crisp. For upscaling (making an image larger), the browser has to stretch existing pixels to fill new space — this can introduce visible blurring, especially past 150% of the original size.

When to use this tool — and when not to

• Good fit: resizing photos for email attachments, social profile pictures, website thumbnails, blog post images, or app mockups.
• Good fit: quick bulk work where you just need a specific pixel width (e.g. 1080 px for Instagram, 1200 px for Twitter/X cards).
• Good fit: converting between JPEG, PNG, and WebP at the same time as resizing.
• Not ideal: very large batches (50+ images) — a desktop tool like IrfanView or a CLI script is faster for bulk jobs.
• Not ideal: vector graphics (SVG, AI, EPS) — those scale losslessly and don't need a pixel resizer; edit them in their native format.
• Not ideal: when you need to crop, not just scale — a dedicated crop tool gives you more control over the composition.

Your image stays private

Everything happens inside your browser tab. The file is read from your device, processed in memory, and written back to your device when you download. No image data is ever sent to a server or stored anywhere online. You can use this tool on sensitive photos, screenshots, or internal documents without worry.

Common image size reference

Ready to resize? Drop your image into the tool at the top of the page and you'll have a properly sized file in under ten seconds.