Image Resizer
Resize JPG, PNG & WEBP to any dimension — runs in your browser
Drag & drop image here
Supports JPG, PNG, WEBP
What is Image Resizer?
An image resizer lets you change the pixel dimensions of an image — making it larger, smaller, or fitted to specific dimensions for a particular use case. Images come in many different sizes: a photo from a modern smartphone might be 4000×3000 pixels and 12 megapixels, far too large for a website thumbnail, email attachment, social media profile picture, or document header.
Resizing is one of the most common image editing tasks. Web developers resize hero images to fit layout breakpoints. Social media managers resize photos to meet platform-specific dimensions (Instagram square: 1080×1080, Twitter header: 1500×500, Facebook cover: 820×312). Designers prepare images at multiple sizes for responsive design. Document authors resize images to fit within Word or PDF page layouts.
Altairys's Image Resizer lets you specify exact pixel dimensions with the option to lock the aspect ratio so images aren't distorted. You can set a maximum width or height for responsive use, set both dimensions for exact sizing, or percentage-scale to increase or decrease by a specific factor. The tool supports JPEG, PNG, WebP, and other formats, and processes images entirely in your browser — no server uploads required. Multiple images can be resized in batch with the same dimensions applied to all.
How to Use Image Resizer
- Upload your image(s)
Drag and drop one or multiple images to resize in batch.
- Set dimensions
Enter width, height, or percentage. Toggle lock to preserve aspect ratio.
- Choose output format
Select JPEG, PNG, or WebP and set the quality level.
- Download resized images
Download each resized image individually or all as a ZIP file.
Key Benefits
Prevent distortion by automatically adjusting height when you change width.
Resize multiple images at once with the same target dimensions.
All resizing runs in your browser — images never leave your device.
See the resized image and new file size before downloading.
Supported Formats
Frequently Asked Questions
Downscaling (making smaller) generally preserves quality well. Upscaling (making larger) causes pixelation as no new detail can be invented. Use the highest-resolution source possible.
Locking the aspect ratio means that when you change the width, the height adjusts proportionally, and vice versa. This prevents the image from appearing stretched or squashed.
Instagram feed: 1080×1080 (square) or 1080×1350 (portrait). Twitter/X post: 1200×675. Facebook feed: 1200×630. LinkedIn post: 1200×627. LinkedIn banner: 1584×396.
Yes — when you select PNG as the output format, transparency (alpha channel) is preserved in the resized image.
Enter a percentage (e.g., 50%) to reduce or increase the image by that factor. A 4000px wide image at 50% becomes 2000px wide.