Resize Images in Bulk — Free, Fast, Offline

XnResize resizes thousands of photos in one pass on Windows 11 and 10, macOS and Linux. Set a width, a height, a percentage or a longest side, choose the resampling quality, and apply it to a whole folder. Everything runs on your machine — no upload, no file size limit and no watermark on the output.

Batch resizing at a glance

• Resize by: pixels, percentage, longest side, or fit inside a bounding box
• Aspect ratio: preserved by default, can be unlocked for exact dimensions
• Resampling: Lanczos, bicubic and other filters for sharp downscaling
• Files per batch: no limit — folders, sub-folders or a drag-and-drop selection
• Output format: convert while resizing, to JPEG, PNG, WebP, TIFF and more
• Privacy: fully offline, nothing leaves your computer
• Platforms: Windows 10/11, macOS (Intel & Apple Silicon), Linux
• Licence: free for private, educational and non-profit use

How to batch resize photos

1. Open XnResize and drag your photos or a folder into the file list.
2. Choose how to resize: a maximum width and height, a percentage, or a longest side. Keep Preserve aspect ratio ticked unless you need exact dimensions.
3. Pick the resampling filter. Lanczos gives the sharpest results when reducing size.
4. Set the destination folder and output format, then click Convert.

For more than a resize — watermark, crop, rename, metadata — use XnConvert, which chains up to 80 actions over the same batch. See also our step-by-step guide: how to resize images without losing quality.

Resizing without losing quality

Quality loss when resizing comes from two separate things: the resampling itself, and the compression applied when saving. Both are controllable.

• Downscale in one step rather than repeatedly — each pass loses detail
• Use Lanczos for reduction; it preserves edges better than bilinear
• Save at JPEG quality 90+, or export to PNG, TIFF or lossless WebP when the image will be edited again later
• Keep the originals — write the resized copies to a separate output folder
• Avoid upscaling: enlarging cannot recover detail that was never captured

Common batch resize tasks

• Photos for the web — cap the longest side at 1920 px and export as WebP or JPEG
• Email attachments — resize to 25 % and keep JPEG quality at 85
• A camera shoot — resize RAW files and export JPEG proofs in one operation
• iPhone photos — resize and convert HEIC to JPEG at once
• Thumbnails — fit inside a fixed box, with the aspect ratio preserved

Frequently asked questions

Is there a free batch image resizer for Windows?

Yes. XnResize resizes whole folders of photos and is free for private, educational and non-profit use, with no watermark and no limit on the number of files. XnConvert adds resizing to a longer chain of batch actions.

How do I resize images without losing quality?

Reduce dimensions rather than re-compressing: keep the aspect ratio, use the Lanczos resampling filter for downscaling, and export at a high JPEG quality (90 or above) or to a lossless format such as PNG, TIFF or lossless WebP.

Can I resize thousands of images at once?

Yes. Drag an entire folder in, set the target size once, and it is applied to every file. Processing runs on multiple CPU cores, so batches of thousands of photos complete in one pass.

Does resizing keep the aspect ratio?

Yes, by default. You can set a maximum width, a maximum height or a longest side, and the other dimension follows automatically. Ratio locking can be disabled if you need exact dimensions.

Are my photos uploaded anywhere?

No. XnResize and XnConvert run entirely on your computer. Nothing is uploaded, there is no file size limit, and the originals are untouched unless you choose to overwrite them.

Can I resize and convert the format at the same time?

Yes. Both tools let you pick an output format alongside the new dimensions, so a folder of camera RAW or HEIC files can become web-sized JPEG or WebP in a single operation.

What is the difference between XnResize and XnConvert?

XnResize is focused: resize a batch, pick a format, done. XnConvert is the full batch processor, chaining up to 80 actions such as watermarking, cropping, colour adjustment and metadata editing alongside the resize.

Download a free batch image resizer

• Download XnResize 1.11 — the focused batch resizer for Windows, macOS and Linux
• Download XnConvert 1.115.0 — batch resize plus 80 other actions
• NConvert — command-line resizing, for scripts and servers
• How to resize images without losing quality