What is Image Resizer?

Image Resizer is a browser-based tool that changes the pixel dimensions of an image file. No file is uploaded to any server. All processing happens in your browser using the Canvas API. You set the target width and height, choose an output format, and download the result directly to your device.

Supported input formats are JPG, PNG, WebP, and GIF up to 10 MB. Output can be saved as JPG, PNG, or WebP.

How does it work?

Upload an image and set the target dimensions in pixels or as a percentage of the original size. Aspect ratio lock keeps width and height proportional when you change one value. The tool draws the image onto an HTML Canvas element at the new dimensions and exports it as a compressed file in your chosen format.

Pixel dimensions and compression format together determine the output file size. A 4000x3000 image resized to 800x600 and saved as JPG at 80% quality typically drops from several megabytes to under 200 KB. WebP produces smaller files than JPG at the same visual quality setting.

Resizing affects pixel count only. Upscaling, adding pixels where none existed, always reduces sharpness regardless of the tool used. Downscaling reduces sharpness much less noticeably.

When should you use Image Resizer?

Most social media platforms enforce pixel limits on profile photos and uploaded images. LinkedIn profile photos must be at least 400x400 pixels. WhatsApp compresses images automatically, but uploading a smaller image beforehand reduces the distortion caused by its own compression.

E-commerce product listings have specific dimension requirements per marketplace. Amazon requires images of at least 1000 pixels on the longest side for zoom functionality. Flipkart, Meesho, and Myntra each have their own specifications. Resizing before upload prevents the platform from doing it automatically, which often produces blurry or oddly cropped results.

For websites and blogs, oversized images increase page load times for every visitor. Resizing images to roughly the display size before uploading is one of the lowest-effort ways to improve page speed.

Tips to get the best results

For images with text, sharp lines, or transparency, use PNG format. JPG and WebP use lossy compression that can blur fine detail.
Set JPG quality to 80-85%. Going below 75% introduces visible compression artifacts. Going above 90% inflates file size without a visible improvement.
If the platform specifies exact dimensions, turn off aspect ratio lock and enter width and height precisely to avoid automatic cropping at upload.
Test the resized image by zooming in before downloading. Upscaling artifacts are easy to miss at normal zoom levels.

Image Tools