Image Resizer
Resize JPG, PNG and WebP images to an exact width and height or by percentage, keep proportions or stretch, change format, and download individually or as a ZIP.
Drop images to resize
Resize one photo or a whole batch to exact pixels or a percentage.
How to use Image Resizer
Simple steps to get your task done in seconds
Add images
Drop one or more JPG, PNG, WebP, GIF or BMP images.
Set the size
Type a width and or height in pixels, or a percentage. Keep proportions or stretch to an exact size.
Download
Download each resized image or all of them as a ZIP.
How In-Browser Image Resizing Works
ZapPebble resizes single or batch images locally using the browser's hardware-accelerated 2D Canvas engine. The resizer employs high-quality bicubic resampling (imageSmoothingQuality = 'high') to scale pixel dimensions up or down while preserving sharpness and color depth. You can resize by exact target pixels or by percentage, lock aspect ratios, convert formats, and download results as individual files or a consolidated ZIP archive.
| Resizing Mode | Options & Boundaries | Technical Details |
|---|---|---|
| By Exact Pixels | Custom Width × Height (Up to 12,000 px) | Aspect ratio lock automatically calculates proportional height when width is changed. |
| By Percentage | 1% to 500% Scale | Ideal for batch processing photos with mixed orientations or dimensions. |
| Format Re-Encoding | Original, JPEG, PNG, WebP | Convert format simultaneously while scaling dimensions. |
Practical Example: Downscaling High-Resolution Camera Photos for a Blog
You shot 10 product photographs on a DSLR camera at 6000×4000 pixels (average 12 MB per photo). Uploading 6000px images to your blog will cause slow page loads and poor Core Web Vitals (LCP).
1280 px · Aspect ratio = Locked · Format = WebP.- All 10 photos are scaled down to 1280×853 pixels in under 3 seconds.
- Total folder size drops from 120 MB down to 2.1 MB (98% reduction).
- Click "Download All as ZIP" to receive all 10 resized WebP files ready for instant publishing.
Important Scaling Principles & Memory Limits
Downscaling images produces clean, sharp results by averaging pixel data. Upscaling small images beyond 100% stretches existing pixels and cannot invent new photographic detail.
ZapPebble zeroes canvas widths immediately after rendering each image. This prevents memory leaks and ensures even low-power smartphones can process large batches smoothly.
Your personal photographs, private family albums, and internal design assets are processed exclusively in local browser RAM. Nothing is uploaded to remote servers.
Related Image Tools
Frequently Asked Questions
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Other utilities that pair well with Image Resizer
Image Compressor
Compress JPG, PNG, and WebP images directly in your browser without uploading your files.
Image Converter
Convert JPG, PNG, and WebP images directly in your browser without uploading your files.
JPG to PDF
Combine multiple JPG, PNG or WebP images into one PDF and download it. Nothing is uploaded.