Image Resizer
Resize images to custom dimensions.
About This Tool
Image Resizer is a free online tool that lets you resize any image to exact pixel dimensions or choose from common presets — all in your browser without uploading. Set custom width and height, lock the aspect ratio for proportional scaling, and export in JPEG, PNG, or WebP format. It works with photos, screenshots, banners, and any image file.
Resizing runs entirely via the HTML5 Canvas API. No files are sent to a server, no account is required, and the tool works on desktop and mobile browsers. A live preview shows the result before you download. The aspect ratio lock prevents accidental stretching by automatically recalculating the companion dimension whenever you change width or height.
Image Resizer is commonly used by social media managers preparing images for platform-specific dimensions, developers generating thumbnails or responsive image sizes, and designers scaling assets for print and web deliverables. For batch resizing, consider using this tool sequentially or pairing it with a local image editing script.
Drag & drop files here or click to browse
How to Use
- 1
Upload your image by clicking the upload area or dragging and dropping a file.
- 2
Enter the target width and height, or choose a preset size. Enable the aspect ratio lock to scale proportionally.
- 3
Download the resized image in your chosen format.
- 4
Toggle the aspect ratio lock to freely set custom dimensions if needed.
- 5
Choose JPEG for photos, PNG for graphics with sharp edges, or WebP for optimized web images.
Features
Aspect Ratio Lock
Lock the aspect ratio to automatically calculate the correct height when you change the width, and vice versa.
Preset Sizes
Choose from common presets like HD (1920×1080), Instagram square, and more for quick resizing.
Format Choice
Export your resized image as JPEG, PNG, or WebP to match your needs.
Browser-Based
All resizing is done locally using the Canvas API. Your images never leave your device.
Common use cases
- ›Resize photos to exact platform dimensions for Twitter, Facebook, LinkedIn, or Instagram.
- ›Scale down large images to reduce page load time before uploading to a website or CMS.
- ›Generate thumbnail-sized versions of product images for e-commerce listings.
- ›Resize screenshots or mockups to fit presentation slides or documentation templates.
Read our guide
Image Resizer — Complete Guide →FAQ
What image formats are supported?
JPEG, PNG, WebP, and most common image formats.
Can I maintain the aspect ratio?
Yes, use the lock toggle to automatically calculate the other dimension.
What presets are available?
Common presets include HD (1920×1080), Full HD, 4K, Instagram square (1080×1080), Instagram portrait, and others for social media and web use.
Can I upscale an image?
Yes, you can enter dimensions larger than the original. However, upscaling cannot add detail — the result will appear blurry if scaled too far beyond the original resolution.
Is there a maximum file size?
No hard limit — the Canvas API handles large images. For very large source images (above 20 megapixels), processing may take a few seconds depending on your device.