What is the Image Resizer?

The Image Resizer is a free online tool that lets you change the dimensions or file size of any image directly in your browser. Upload a JPEG, PNG, or WebP file, choose how you want to resize it, pick an output format, and download the result — no software installation, no account required.

All processing happens entirely in your browser using the Canvas API. Your images never leave your device.

---

Three Ways to Resize

By dimensions

Enter a specific width and height in pixels. The aspect ratio lock keeps your image proportionally correct by default — change the width, and the height updates automatically to match the original ratio. Unlock it to set each dimension independently if you need a specific crop size.

By percentage

Scale your image up or down by a percentage of its original size. 50% halves both dimensions (and reduces file size to roughly a quarter, since area scales by the square of the dimension change). Values above 100% upscale the image.

By file size target

Specify the maximum output file size in kilobytes. The tool uses a binary search on compression quality to find the smallest quality setting that meets the target. If the target is very aggressive, it also reduces the image dimensions. This mode is useful when you need to hit a hard limit — email attachment caps, CMS upload limits, or platform requirements.

---

Output Formats

JPEG — Best for photographs and images with complex color gradients. Uses lossy compression, which produces very small files at moderate quality settings. Does not support transparency.

PNG — Best for screenshots, logos, graphics with flat areas of color, and images that need a transparent background. Uses lossless compression, so quality is fully preserved. File sizes are typically larger than JPEG for photographs.

WebP — A modern format developed by Google. Produces files roughly 25–35% smaller than JPEG at equivalent quality. Supports transparency (like PNG) and lossy compression (like JPEG). Supported by all major browsers since 2020.

---

Quality Setting

For JPEG and WebP, the quality slider controls the lossy compression trade-off. Quality 85 is generally indistinguishable from the original on screen while producing files 3–5× smaller. Quality 70–80 is suitable for web thumbnails and most use cases where file size matters. Quality below 60 introduces visible artifacts and is rarely appropriate outside of aggressive optimization scenarios.

PNG does not use a quality setting — it always uses lossless compression, so quality is always 100%.

---

When to Use Each Mode

Dimensions mode is the right choice when you have a specific size requirement — a banner that must be exactly 1200×628px, a profile picture capped at 400×400px, or a thumbnail grid that needs uniform sizes.

Percentage mode is fastest when you want to scale down without calculating exact pixel values. Reducing to 50% or 75% is a quick way to make images smaller for email or sharing without overthinking dimensions.

File size mode is the most practical when you're working within a constraint. If you know an upload must be under 500KB, or an email attachment can't exceed 1MB, enter the target and let the tool figure out the compression settings. It adjusts quality first (preserving your dimensions) and scales dimensions as a last resort if the target is very small.

---

Batch Resizing

The free version of this tool resizes one image at a time. Batch resizing — processing multiple images in a single operation — is available as a premium feature for users with a credits plan.

---

Privacy

Your images are processed entirely within your browser. Nothing is uploaded to any server, and no image data is stored, logged, or transmitted. The tool works offline once the page has loaded.