LocalKit

Bulk Image Resizer

Resize multiple images at once and download them as a ZIP — entirely in your browser. No upload, no sign-up, no watermark.

Your files never leave your device. All processing happens in your browser.

Resize mode

Images narrower than this are kept as-is.

Output format

Drop images here or browse

JPG, PNG, WebP, GIF — multiple files at once

How to Resize Images in Bulk

  1. Choose a resize mode. Max width scales images down to a maximum width while keeping each image's aspect ratio — useful for preparing photos for web upload. Scale % multiplies all images by a fixed percentage — useful when you need to halve a folder of images for email or preview.
  2. Set the target value. Enter a max width in pixels (e.g. 1200) or a percentage (e.g. 50). Images narrower than the max width are left at their original size.
  3. Pick an output format. JPG is the smallest for photos. PNG is lossless and keeps transparency. WebP produces the smallest files at a given quality. Use the quality slider for JPG and WebP to balance size and sharpness.
  4. Add your images. Drag a folder or multiple files onto the drop zone, or click to browse. All processing happens locally — nothing is uploaded.
  5. Click “Resize & Download ZIP”. Each image is processed in order. The file list shows live status: a spinner while processing, a green ✓ when done, a red ✗ if something went wrong.
  6. Download your files. When processing is complete, click Download ZIP to save all resized images in a single archive, or click the individual download arrow (↓) next to any file for a one-off save.

Common Use Cases

  • Website images. Resize a batch of product photos to max 1200 px wide before uploading to an e-commerce platform or CMS.
  • Email attachments. Scale photos to 50% or 25% before attaching — most email clients choke on multi-megabyte images.
  • Client deliverables. Produce a web-ready set alongside the originals without manually resizing each file.
  • Photo archives. Create a smaller preview set from a holiday photo library without touching the originals on disk.
  • Consistent sizes. Use max-width mode to make a folder of mixed-resolution images all conform to the same width, keeping their individual aspect ratios.

Tips for Best Results

  • JPG quality 80–85 is a good default for photos: files are 40–60% smaller than the originals with barely visible quality loss.
  • WebP at quality 80 is typically 25–35% smaller than JPG at the same quality — use it if you are uploading to a site that accepts WebP.
  • Use PNG only when you need transparency. Lossless PNG produces much larger files than JPG for photographs.
  • Process one batch at a time. If you have many large images, break them into batches of 20–30 to avoid running out of browser memory.

Frequently Asked Questions

Are my images uploaded to a server?

No. Every image is processed entirely in your browser using the Canvas API. Your files never leave your device — you can verify this in the Network panel: no upload request is made at any point.

How many images can I resize at once?

There is no hard limit on the number of files because nothing is uploaded. In practice, your browser's available memory is the only constraint. Batches of 20–50 photos work well on most devices. Very large batches (100+) of high-resolution photos may be slow or exhaust memory on lower-end devices.

What is the difference between "Max width" and "Scale %" modes?

"Max width" sets a ceiling: images wider than your chosen value are scaled down proportionally; images that are already narrower are kept at their original size. "Scale %" multiplies every image's dimensions by a fixed percentage — for example 50% halves both the width and height of every image, regardless of the original size.

Can I download individual files instead of a ZIP?

Yes. After processing, each row in the file list has a small download arrow (↓) on the right. Click it to save that single file. The ZIP button downloads everything in one go.

What if some images fail to process?

Each file is processed independently. If one image fails (e.g. it is corrupt), the rest continue. Failed files are marked with a red ✗ and an error message. Successfully processed files are still included in the ZIP.

Does the bulk resizer keep the aspect ratio?

Yes. Both modes maintain each image's original aspect ratio. "Max width" scales down proportionally from the width; "Scale %" multiplies both dimensions by the same factor. No image is cropped or stretched.

Related Tools