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Bulk Image Resizer

Resize dozens of images to the same dimensions in a single operation. Upload a batch of JPG, PNG, or WebP images, set your target width and height (or percentage scale), and download all the resized files at once. Ideal for preparing image libraries for websites, apps, and social media. Everything runs in your browser — no files are ever uploaded.

🔒 100% private — never uploaded⚡ Instant results🆓 Always free🚫 No signup required🖥️ Runs in your browser
🖼️
Drop images here or click to upload
Multiple images supported

How to Use Bulk Image Resizer

  1. 1

    Upload your images

    Click the upload area or drag and drop multiple JPG, PNG, or WebP files. You can add them all at once — there is no per-batch limit beyond your browser memory.

  2. 2

    Set target dimensions

    Enter the target width and height in pixels, or choose a percentage scale. Enable aspect ratio lock to resize proportionally without distorting any image.

  3. 3

    Choose output format

    Select JPG, PNG, or WebP as the output format. All images in the batch will be converted to this format. Adjust JPG/WebP quality if needed.

  4. 4

    Resize all images

    Click the Resize All button. Each image is processed independently in the browser — the progress bar shows completion across the batch.

  5. 5

    Download

    Download each resized image individually, or click Download All to get every file packaged together in a zip archive.

When to Use This Tool

Website image libraries
Websites need images at specific display dimensions. Resize an entire product catalogue, blog header set, or gallery to the exact pixel width in one operation.
Social media content batches
Creating a week of Instagram posts or Twitter cards? Upload all your source images and resize the batch to the platform-standard dimensions simultaneously.
App asset preparation
Mobile and web apps use the same icon or image asset at multiple resolutions. Resize a batch of originals to all the required sizes and download them together.
E-commerce product photos
Marketplaces require all product images to be the same dimensions. Upload your entire product photo library and standardise sizes in seconds.
Email newsletter images
Email templates have strict width constraints (usually 600px). Bulk resize all images for an email campaign to the correct width before building the newsletter.

Quick Reference

FeatureDetail
Supported formatsJPG, PNG, WebP
Batch sizeUnlimited (browser memory permitting)
Resize modesPixels or percentage
Aspect ratio lockYes
Output formatJPG, PNG, or WebP (user choice for whole batch)
Bulk downloadYes — ZIP archive of all resized files
Server uploadNever — 100% browser-based
CostFree, no account needed

About Bulk Image Resizer

The Bulk Image Resizer lets you resize dozens of images simultaneously to a consistent size — saving hours of manual resizing in image editors. Upload multiple photos at once, set your target dimensions or scale percentage, and download all resized images in a single ZIP file. This is the fastest way to prepare image batches for websites, social media posting, product listings, or presentations.

Bulk resizing is essential for:

  • Resizing a batch of product photos to the exact dimensions required by an e-commerce platform
  • Standardizing photo sizes before uploading to a CMS or website gallery
  • Preparing a set of social media images to consistent dimensions (e.g., all to 1080×1080px for Instagram)
  • Scaling down a folder of high-resolution photos for email or web sharing
  • Resizing a batch of screenshots for a documentation or user guide

Resizing is performed in the browser using the HTML5 Canvas API. Each uploaded image is drawn onto a canvas at the target dimensions, and the browser's built-in bilinear interpolation algorithm handles the scaling math. This algorithm averages surrounding pixel values during downscaling to reduce aliasing, producing sharper results than nearest-neighbor scaling. For upscaling, bicubic interpolation approximation is used. All images are processed in parallel using Web Workers where supported, which keeps the UI responsive even when processing 50+ images.

Input formats: JPG, PNG, WebP, BMP, GIF. Resize modes: exact width×height (with option to maintain aspect ratio), width only (height auto-calculated), height only (width auto-calculated), or percentage scale. Output formats: JPG or PNG. Batch size: up to 100 images per session. Download: individual files or a ZIP archive.

All processing happens locally in your browser — nothing is uploaded to any server. Your images stay on your device throughout the entire operation. After bulk resizing, you may want to use the Image Compressor to further reduce file sizes for web delivery.

Pro Tips for Bulk Image Resizer

1

Use "width only" mode with aspect ratio lock when resizing photos with mixed orientations — this prevents portrait photos from being stretched to match landscape dimensions.

2

For web images, resize to 1.5× the display size for retina/HiDPI screens — a 600px wide column needs 900px images to look sharp on modern displays.

3

Process RAW formats by converting to JPG first — the bulk resizer handles JPG much faster than lossless formats, and for web delivery JPG is almost always the right output format.

4

When preparing e-commerce images, check the platform's exact dimension requirements first — Amazon requires 1000px minimum on the longest side, while Etsy recommends 2000px.

Frequently Asked Questions

How many images can I resize at once?+
There is no hard limit on batch size — you can add as many images as your browser memory allows. For most computers, batches of 50–100 images process smoothly. For very large batches (200+), process in groups to avoid browser slowdown and potential out-of-memory errors.
Will all images be resized to exactly the same dimensions?+
Yes. All images receive the same target width and height. If aspect ratio lock is enabled, each image is scaled proportionally to fit within the target dimensions without cropping — so some images may not hit exactly the target height if their aspect ratio differs. Turn off aspect ratio lock to force all images to exactly the specified width × height, which may stretch some images.
Can I use different sizes for different images in the same batch?+
No — the bulk resizer applies one target size to all images. If you need different sizes for different images, process each separately with the standard Image Resizer tool, or split your batch into groups by size and process each group.
What output format should I use for my batch?+
For photographs and general content, JPG gives the smallest file sizes. For images that require transparency or lossless quality, use PNG. For web assets, WebP gives the best combination of quality and compression. All images in the batch are converted to the same format you select.
Can I change the file name pattern for the output files?+
Output files are named with the original filename plus a "-resized" suffix and the new extension. This keeps your original filenames recognisable while making it clear which files have been processed.
Is bulk resizing slower than resizing one image at a time?+
Each image takes roughly the same time regardless of whether it is in a batch. The browser processes images sequentially, so a batch of 20 images takes approximately 20 times as long as a single image. Most images process in under a second, so a batch of 20 completes in about 5–10 seconds.

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Your input is processed locally in your browser and is never stored, transmitted, or shared with any server. See our Privacy Policy.

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