Bulk Image Resizer
Resize many images at once by longest side, width or percentage — ZIP download.
About this tool
Set a rule (no larger than 1600 px, exactly 800 px wide, or 50%), optionally a format and quality, then drop the images. Each is resized in your browser with proportions kept; download individually or as a ZIP.
Sizing a batch sensibly
The useful rule for mixed portrait and landscape photos is longest side: “no larger than 1600 px” makes every image web-sized without distorting any of them, and never enlarges the small ones (upscaling a small photo only makes it blurry — see the upscaler for when that's actually wanted). Exact width suits catalogue thumbnails and email signatures; percentage suits “half size of whatever these are”. Format matters as much as pixels for file size: WebP is a quarter to a third smaller than JPG at the same look, JPG is what every old system accepts, PNG stays lossless and large. Photos with transparency get a white background when saved as JPG, because JPG has no transparency. All processing is on-device, so a hundred phone photos take about a minute and nothing is uploaded — the honest difference from batch sites that hold your holiday pictures on a server. Metadata (including location) is dropped along the way. Single images with finer control: the image resizer and compress to a target size; the maths of megapixels versus print size is in How to reduce image file size without wrecking it.
Frequently asked questions
Are the proportions kept?
Always — every rule scales width and height together. There is no stretching option, deliberately.
Will small images be enlarged?
Not by the longest-side rule; they pass through unchanged. Exact width and percentage rules do scale up if you ask, at a visible cost in sharpness.
How many images can I resize?
As many as your device handles — hundreds is fine on a laptop. They're processed one at a time to keep memory steady, with a progress bar.
Is anything uploaded?
No. Resizing, format conversion and the ZIP are all made in your browser.