ALL IMAGE TOOLS56
Image Resizer
Resize Images Online — Free, High-Quality Resampling
Resize to exact dimensions or social media presets with Lanczos3 quality.
About Image Resizer
Need to resize an image for social media, a website, or a specific pixel size? This tool uses Lanczos3 resampling (via the pica library) for the highest-quality downscaling and upscaling — producing sharp, clean results without the blurriness or aliasing artifacts that basic resizing methods create. Choose from six presets — Instagram Post (1080x1080), Instagram Story (1080x1920), Twitter Header (1500x500), LinkedIn Banner (1584x396), Passport Photo (600x600), and YouTube Thumbnail (1280x720) — or enter custom dimensions with an optional aspect ratio lock to prevent distortion, or scale the original by a percentage. Whether you are preparing product images for an online store, creating consistently sized thumbnails for a blog, or formatting photos to meet a specific platform's requirements, this tool handles it in seconds. The aspect ratio lock ensures your images are never stretched or squished. Everything runs in your browser with no upload required, so your images remain completely private. Supports JPG, PNG, WebP, AVIF, BMP, and GIF input formats.
Questions
What is Lanczos3 resampling?
Lanczos3 is a high-quality image resampling algorithm that produces sharp, artifact-free results when scaling images up or down. It's the same algorithm used by professional image editors like Photoshop.
Will resizing make my image blurry?
Downscaling (making smaller) always looks great with Lanczos3 resampling. Upscaling (making larger) preserves detail well but cannot add information that isn't in the original — very large upscales may appear slightly soft.
What dimensions should I use for social media?
Use the preset buttons: Instagram Post is 1080×1080, Instagram Story is 1080×1920, Twitter Header is 1500×500, LinkedIn Banner is 1584×396, YouTube Thumbnail is 1280×720.
What format does the resized image come out in?
It follows the input: PNG and GIF sources come out as PNG (keeping transparency), WebP and AVIF come out as WebP, and JPG or BMP come out as JPG. There's no format picker here — resize first, then run the result through a converter tool if you need a different format.
Is there a maximum output size?
Yes — both dimensions are capped at 8192 px, and percentage mode goes up to 500% of the original, still within that cap. Anything larger is clamped to the limit rather than rejected.
Is my file uploaded to a server?
No. Transmute processes everything locally in your browser using JavaScript and WebAssembly. Your files never leave your device — there is no server, no upload, no cloud processing.