// resize images by pixels or percentage — nothing uploaded
Free browser-based image resizer. Resize images by pixels, percentage, or aspect ratio. Batch resize up to 20 images with JPEG, PNG, and WebP output. No upload to server, no sign-up required.
Click or drag & drop images
JPEG · PNG · WebP · GIF — max 20 filesNo images yet
Upload up to 20 images at onceDrag and drop or click to select up to 20 images. JPEG, PNG, WebP, and GIF are all supported.
Choose Pixels for exact dimensions, Percent to scale by ratio, or Fit Box to constrain within a max size.
Click Resize All and download each file individually, or grab them all as a ZIP archive.
A free browser-based image resizer using the HTML Canvas API. Resize by exact pixel dimensions with optional aspect-ratio lock, by percentage scale, or fit within a bounding box. Batch process up to 20 files with JPEG/PNG/WebP output and ZIP download — no server, no sign-up.
No. All resizing happens in your browser using the HTML Canvas API. Your images never leave your device — no data is sent to any server at any point. This makes the tool safe for confidential, proprietary, or personal photos.
Fit Box mode resizes an image so that it fits entirely within a bounding rectangle you specify, while maintaining its original aspect ratio. It only scales down — images smaller than the box are not upscaled. This is useful for standardizing large batches of images to a maximum size, such as 1920×1080 for web use, without distorting portrait or landscape photos.
In Pixels mode, the lock button (🔒) keeps the width-to-height ratio constant. When you change the width, the height updates automatically, and vice versa. The ratio is calculated from the original image dimensions when you upload the file. Click the lock to toggle it off if you want to set both dimensions independently.
Yes, in Pixels and Percent modes you can set dimensions larger than the original — the canvas will scale the image up. However, upscaling a raster image (JPEG, PNG) always reduces quality because no new pixel data is added; the browser simply stretches the existing pixels. For clean upscaling, use a dedicated AI upscaling tool. Fit Box mode never upscales.
PNG uses lossless compression, so the file size is determined by image complexity and dimensions — not a quality setting. Resizing to the same pixel count with a different aspect may produce a different file size. Converting a large PNG to JPEG or WebP with this tool will usually produce a much smaller file.
This tool is limited by your browser's maximum canvas dimensions, which is typically 16384×16384 pixels in modern browsers. Very large images (above ~50 MP) may cause the browser tab to run out of memory. For most practical use cases up to 4K resolution, the tool works without issues.
Image dimensions directly affect file size, page load speed, and storage use. A 4000×3000 pixel photo from a modern smartphone camera can be 6–12 MB as a JPEG. Resized to 1200×900 for web display, the same image might be 150–300 KB — a reduction of 95% or more. Serving oversized images wastes bandwidth and slows down your website for every visitor.
Beyond the web, image resizing is essential for email attachments, social media uploads that enforce dimension limits, product photography for e-commerce platforms, and archival workflows where storage space is a concern.
Each resize mode serves a different use case. Pixels mode is for when you need exact output dimensions — useful for social media image specifications (e.g. Twitter header: 1500×500px) or CMS upload requirements. Percent mode scales the image by a ratio — useful for batch reducing a folder of images to 50% of their original size while keeping all proportions and relative sizes identical. Fit Box mode is the most practical for web optimization: you specify a maximum size (e.g. 1920×1080) and the tool scales each image down proportionally to fit within that box, never upscaling and never distorting the aspect ratio. Different images in your batch can have different aspect ratios and still all fit correctly.
For web use, WebP at quality 85 is the best choice: smaller than JPEG, better transparency than PNG, and supported in all modern browsers. For compatibility with older tools, email clients, or systems that require JPEG or PNG specifically, use those formats. The Original option keeps the same MIME type as the input file — useful when you only want to change dimensions without changing format.