Batch Image Resizer

📖 About this tool

Batch Image Resizer brings a whole folder of pictures to one consistent pixel size. It is the tool for the moments when a platform dictates the dimensions: a marketplace that only accepts 800 by 800 product shots, a newsletter header that has to be 900 by 383, a print shop that wants 300 dpi, or simply a phone gallery full of 4000 by 3000 originals that are far too heavy to send over chat. Drop the batch in, choose how you want to measure, and collect every result a few seconds later as individual files or a single ZIP archive.

Four measurement modes cover practically every request: an exact width and height, a percentage scale applied to everything, a cap on the longest side - which is the sensible choice when landscape and portrait shots are mixed together - and a fit-in-box mode that shrinks each image proportionally until it fits inside the frame you specify. The aspect lock is on by default, so whatever numbers you type are corrected against the original ratio and no image ever comes out squashed or stretched.

✨ Features

• Four resize modes - exact pixels, percentage, longest side, or fit in box.
• Batch processing - select any number of images, with a progress bar.
• Aspect ratio lock - the target size is corrected to the original ratio so nothing is distorted.
• Never upscale switch - images already smaller than the target are left untouched instead of being blurred by enlargement.
• Format and quality - keep the original codec or force JPG, WebP or PNG, with quality from 10% to 95%.
• Per-file comparison - the result list shows the pixel dimensions before and after.
• ZIP download - collect every output in one archive.
• Runs locally - nothing is uploaded and it works offline.

🚀 How to use

1. Click Choose images or drag files onto the dashed area; multiple selection works. Load samples to try it first.
2. Pick a resize mode and enter its parameters - width and height, percentage, longest side, or the box.
3. Decide whether to lock the aspect ratio and whether upscaling is allowed, then set format and quality.
4. Press Resize and watch the progress bar; the result list then shows the dimension change per image.
5. Download single files, or grab everything with Download all as ZIP.

⚠️ Notes

• Downscaling is irreversible and upscaling cannot recover detail - keep your originals.
• Fit in box only shrinks; it never blows a small image up to fill the frame.
• Turning the aspect lock off will stretch images to the exact pixels you typed, which is rarely desirable.
• Forcing PNG can increase file size because the format is lossless.
• Images with sides in the tens of thousands of pixels may exceed browser canvas limits.