Free Online Image Resizer

The Tooloogle Image Resizer changes the dimensions of any JPG, PNG, or WebP image directly in your browser. Drop a file onto the upload zone, choose between Pixels mode (type exact width and height with optional aspect-ratio lock) or Percent mode (scale uniformly from 1% to 500%), pick an output format, and download the resized image with one click. No signup, no upload to a server, no watermark — the whole pipeline runs in your tab using the native HTML5 Canvas API. Perfect for shrinking phone photos before email, generating multiple sizes of a logo for social profiles, downscaling hero images for faster page loads, or upscaling small icons to fit a higher-DPI layout.

What It Does & How It Works

When you select an image, the resizer reads its native pixel dimensions, displays a preview, and pre-fills the target width and height fields. As you adjust either field with aspect lock on, the other field recomputes automatically using the original aspect ratio so your image never stretches. In Percent mode, a single slider/input from 1% to 500% scales both axes together — ideal when you don't care about exact pixel counts and just want "half size" or "double size". Hit Resize and the tool draws your image to a freshly-sized off-screen <canvas>, calls canvas.toBlob() with your chosen format and quality, and produces a download link with a sensible filename like my-photo-800x600.webp. Everything is done locally; nothing is uploaded.

Features

Two resize modes — Pixels (exact W×H with aspect lock) or Percent (uniform 1–500%).
Aspect-ratio lock — on by default in Pixels mode; edit one field and the other recomputes from the original ratio. Toggle off for free-form stretching when you actually want it.
Three output formats — PNG (lossless, preserves alpha), JPEG (small, no transparency), and WebP (modern, best compression at high quality).
Quality slider — for JPEG and WebP outputs; defaults to 0.92 (very high) so visual quality is preserved.
Instant preview — see the source image before resizing; see the output size right after.
Drag & drop upload — powered by the reusable Tooloogle file dropzone; click anywhere on the zone to browse, or drop a file from your file manager.
Smart filename — downloads as <original-name>-<W>x<H>.<ext> so multiple resizes never overwrite each other.
Browser-only — uses native Canvas + toBlob. No file ever leaves your device. Safe for screenshots that contain personal data, draft work, NDA images, anything.

How to Use the Image Resizer

Upload — drop a JPG, PNG, or WebP onto the upload zone, or click to open the file picker.
Pick a mode — choose Pixels for exact dimensions, or Percent for uniform scaling.
Set the target size — in Pixels mode, type the new width or height (the other recomputes if aspect lock is on); in Percent mode, type a percentage between 1 and 500.
Choose the output format — PNG for transparency, JPEG for smallest non-transparent files, WebP for the best size-quality tradeoff in modern browsers.
Adjust quality (JPEG / WebP only) — drag the quality slider; 0.85–0.95 is a sensible range for most web use.
Click Resize — the new image is rendered to a canvas and a download link appears.
Download — click the link; the file is saved with a descriptive name including the new dimensions.

Common Use Cases

Shrinking 12-megapixel phone photos to a manageable 1200×800 before emailing them or attaching to a support ticket. Generating profile-picture variants for LinkedIn (400×400), Twitter / X (400×400), Facebook (170×170), and Instagram (320×320) from a single source. Producing thumbnails for a blog or e-commerce site without firing up Photoshop. Resizing screenshots to fit a documentation page's max-width column. Downscaling hero images for landing pages so they load faster and pass Core Web Vitals (LCP). Upscaling small logo PNGs by 200–300% for a higher-DPI display so they don't look pixelated on Retina screens. Resizing icons for app store submissions where the store demands exact dimensions. Preparing images for email-marketing campaigns where mailbox providers cap inline image widths. Creating multiple resolutions of the same image for responsive srcset attributes. Quickly checking what an image will look like at half-size before committing to that size in a layout.

Pixels vs. Percent — Which Mode Should You Use?

Pixels mode is for when you have a target dimension in mind — the platform requires exactly 1080×1080, the email template column is exactly 600 pixels wide, the print layout calls for an image at 1200×800. Type the number, leave aspect lock on, and the other dimension follows. Pixels mode is also the safer choice when you need a specific output to fit a UI slot without overflow.

Percent mode is for "just make it smaller" or "make it bigger" situations — you don't care about exact pixel counts, you just want the image cut roughly in half (50%) or doubled (200%). Percent mode is faster when you're processing many images of different starting sizes and want them all reduced by the same proportion.

Aspect-ratio lock applies in Pixels mode only. Percent mode always preserves aspect ratio because it scales both axes together by definition.

Output Format Guide

PNG is lossless and supports transparency — the right choice for logos, icons, screenshots with text, illustrations with sharp edges, and any image where you need alpha channels. PNG files are larger than JPEG or WebP for photos.

JPEG is lossy and does not support transparency — the right choice for photographs and any complex full-frame image where small artifacts are acceptable. The default quality of 0.92 produces visually-indistinguishable results from the source for most photos at a fraction of the size.

WebP is the modern format that supports both lossy and lossless modes plus transparency — the best general-purpose pick for the web because it produces smaller files than both PNG and JPEG at equivalent quality. Supported by every modern browser (Chrome, Firefox, Safari 14+, Edge). When in doubt for web delivery, choose WebP.

Best Practices & Tips

Resize down, not up, whenever possible — downscaling preserves apparent sharpness, while upscaling reveals the resolution limits of the source. If you must upscale, keep it under 2× and accept that fine details will soften. Always pick the smallest dimensions your final use actually requires — saving an extra 200KB per image compounds across a page full of photos. Use WebP for the web by default; fall back to JPEG only when you need broader compatibility (very old browsers or specific tools that reject WebP). Preserve the original file separately — resize a copy. The resizer doesn't modify your source file, but if you re-resize a previously-resized JPEG you double the lossy compression. For screenshots that contain text, prefer PNG output to keep the text crisp; JPEG's lossy compression smears thin strokes. If you need both transparent edges and a small file, WebP is your friend — PNG transparency at the cost of file size becomes WebP transparency at half the size or less.

Privacy & Browser-Based Processing

The Tooloogle Image Resizer never uploads your image. It uses the browser's native FileReader, Image, Canvas, and Blob APIs to read, draw, encode, and download the resized output entirely on your device. You can verify with your browser's DevTools Network tab — no requests fire when you upload, resize, or download. This makes the resizer safe for confidential screenshots, draft marketing assets, NDA-protected client work, medical-record annotations, and any other image you can't hand off to a random web service. As an added bonus, browser-only processing means the tool is fast: the only latency is the time your CPU needs to decode and re-encode the image, with no network round-trip.

Why Choose Tooloogle's Image Resizer?

Tooloogle's resizer is focused, fast, and free. Two clearly-labeled modes (Pixels and Percent) cover every common resize task without burying you in options. Aspect-ratio lock prevents accidental stretching. Three output formats cover every modern delivery scenario. Drag-and-drop upload skips the file-picker dialog. Browser-only processing means your images stay private, the tool is faster than network-bound alternatives, and you can use it without a stable internet connection. Bookmark the page for the next time a friend, client, or coworker sends a 10-megapixel photo that needs to be thumbnail-sized in 30 seconds. Pair the resizer with the Tooloogle Image Compressor when you need to hit a specific file-size target, and with the Tooloogle JPG to WebP Converter, PNG to WebP Converter, and WebP to JPG Converter when you only need a format change without a dimension change.

Image Resizer - Resize Images Online by Pixels or Percent