R
Resizzer
画像ツール 100% ブラウザ内プライバシー

無料オンライン画像リサイズ

写真や画像の寸法を数秒で思い通りに変更。InstagramやYouTubeの規格にワンクリックで合わせられます。

ファイルをドラッグ＆ドロップ、またはクリックして選択

JPG, PNG, WebP（最大50MB）対応 • または Ctrl+V でクリップボードから貼り付け

使い方

Three simple steps to process your files

01

Upload or Drop Photo

Select one or more JPG, PNG, or WebP images from your device, or simply paste an image directly from your clipboard using Ctrl+V.

02

Adjust Pixels or Choose Preset

Specify exact pixel width and height, use the scale percentage slider, or choose from social media presets for Instagram, YouTube, and LinkedIn.

03

Download Optimized Image

Select your preferred output format and quality, then click download. Processing is handled in real-time within your browser.

主な機能

Engineered for speed, fidelity & security

Aspect Ratio Lock

Maintain natural image proportions automatically when adjusting either width or height values.

Social Media Presets

Instant one-click dimensions for Instagram posts, reels, YouTube thumbnails, Twitter banners, and passport photos.

Batch Image Processing

Resize multiple images simultaneously in your browser without waiting for slow server uploads.

Multiple Format Support

Export resized files to JPG, PNG, or modern high-efficiency WebP format.

Zero Quality Loss Resampling

Uses high-quality bicubic canvas interpolation for smooth edges and sharp detail.

100% Client-Side Privacy

Your photos never leave your device. All calculations run strictly in your local browser sandbox.

FAQ

よくある質問

Will resizing an image reduce its clarity or quality?
Our tool applies bicubic canvas interpolation, preserving high sharpness when scaling down and maintaining clarity. To prevent pixelation, avoid enlarging images significantly beyond their original resolution.
Are my uploaded photos stored on your servers?
No. All image resizing is performed 100% locally on your computer using standard HTML5 Canvas APIs. Your files are never sent or stored anywhere.
What file formats are supported?
You can upload and export JPG/JPEG, PNG, WebP, and AVIF images.
What is the maximum file size supported?
Because processing happens directly on your machine, you can process high-resolution images up to 50MB with ease.
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