Preparing social-media images: Twitter header (1500×500), Open Graph card (1200×630), Instagram square (1080×1080), or LinkedIn banner (1200×627). Downsizing high-resolution phone or camera photos to web-safe dimensions before uploading to a blog, CMS, or documentation site. Generating multiple thumbnail sizes (half-size, quarter-size, or custom percentages) from a single source without manual calculations. Reducing file dimensions to fit upload-size restrictions — dropping 500 px from each side is often faster than re-uploading and waiting for server-side processing. Batch-normalising image dimensions across a project by resizing to a standard width while maintaining aspect ratio. Testing responsive designs by quickly previewing how an image looks at different viewport widths.

Select or drag a PNG, JPG, or WebP image into the tool. The file is decoded by your browser's image decoder. Enter target width and height in pixels, or enter a scale percentage (e.g. 50% for half-size). Tick "Lock aspect ratio" to preserve proportions (default: on). For lossy formats (JPG, WebP), adjust the quality slider if needed. PNG always encodes losslessly. Click "Download" to render the image onto a canvas at the new dimensions with high-quality smoothing, then re-encode and download as a blob in the original format.

Aspect ratio lock is on by default. If you uncheck it to force a strict dimension (e.g. forcing a portrait photo into 1200×630), the image will stretch or squash. For distortion-free results, pre-crop in a dedicated tool first. Quality slider only affects JPG and WebP. PNG re-encodes losslessly, so the slider has no effect on PNG output. Browser canvas limits exist. Most desktop browsers cap a single canvas at approximately 16384×16384 pixels; mobile browsers enforce much lower limits. Very large images may fail silently without an error message. Upscaling does not add detail. Resizing a 500×500 image to 2000×2000 stretches existing pixels and produces a blurry result. Always resize down from the highest-resolution source available. File format changes are not supported. A PNG input will always produce PNG output, even if you change the quality slider. Use a separate conversion tool to switch formats.

Resizing is fast for images under 5 MP on modern hardware. Larger images may briefly freeze the browser during canvas rendering. No data is sent to our servers. The entire operation runs in your browser; closing the tab discards all temporary data. Downloaded files retain their original format and colour space. Colour profile conversion is not performed.

Image Resizer

Resize images to any width or height in your browser. Lock aspect ratio, scale down social-media-friendly sizes, download instantly. No upload.

Pick an image (PNG, JPG, WebP)

🔒 Files never leave your browser — no upload, no server, no tracking.

Target dimensions

Width (px)

Height (px)

Lock aspect ratio

Quality 0.90

Quality applies to JPG and WebP outputs only.

Presets

Preview

Pick an image to begin.

What is this for?

Image Resizer is a client-side tool for quickly changing image dimensions without uploading to a server. Feed it a PNG, JPG, or WebP file, specify target width and height (or a scale percentage), and download the result instantly in the original format. The resize happens entirely in your browser using canvas resampling — no file ever leaves your machine.

When to use it

Preparing social-media images: Twitter header (1500×500), Open Graph card (1200×630), Instagram square (1080×1080), or LinkedIn banner (1200×627).
Downsizing high-resolution phone or camera photos to web-safe dimensions before uploading to a blog, CMS, or documentation site.
Generating multiple thumbnail sizes (half-size, quarter-size, or custom percentages) from a single source without manual calculations.
Reducing file dimensions to fit upload-size restrictions — dropping 500 px from each side is often faster than re-uploading and waiting for server-side processing.
Batch-normalising image dimensions across a project by resizing to a standard width while maintaining aspect ratio.
Testing responsive designs by quickly previewing how an image looks at different viewport widths.

How it works

Select or drag a PNG, JPG, or WebP image into the tool. The file is decoded by your browser's image decoder.
Enter target width and height in pixels, or enter a scale percentage (e.g. 50% for half-size). Tick "Lock aspect ratio" to preserve proportions (default: on).
For lossy formats (JPG, WebP), adjust the quality slider if needed. PNG always encodes losslessly.
Click "Download" to render the image onto a canvas at the new dimensions with high-quality smoothing, then re-encode and download as a blob in the original format.

Common gotchas

Aspect ratio lock is on by default. If you uncheck it to force a strict dimension (e.g. forcing a portrait photo into 1200×630), the image will stretch or squash. For distortion-free results, pre-crop in a dedicated tool first.
Quality slider only affects JPG and WebP. PNG re-encodes losslessly, so the slider has no effect on PNG output.
Browser canvas limits exist. Most desktop browsers cap a single canvas at approximately 16384×16384 pixels; mobile browsers enforce much lower limits. Very large images may fail silently without an error message.
Upscaling does not add detail. Resizing a 500×500 image to 2000×2000 stretches existing pixels and produces a blurry result. Always resize down from the highest-resolution source available.
File format changes are not supported. A PNG input will always produce PNG output, even if you change the quality slider. Use a separate conversion tool to switch formats.

Performance notes

Resizing is fast for images under 5 MP on modern hardware. Larger images may briefly freeze the browser during canvas rendering.
No data is sent to our servers. The entire operation runs in your browser; closing the tab discards all temporary data.
Downloaded files retain their original format and colour space. Colour profile conversion is not performed.