Image Resizer
Image ToolsResize PNG, JPG, WebP images by pixels or percentage with aspect lock. Free, private — all processing in your browser.
Drop in an image, set a width and height (or pick a preset), and download the resized version. It keeps the aspect ratio locked by default, so typing a new width updates the height automatically and your image doesn't get squashed. The presets cover the sizes you actually reach for — HD, Full HD, 4K, square and story formats for Instagram, and the exact dimensions for Twitter, Facebook, LinkedIn, and Open Graph share images — plus quick 50% and 25% scale-downs.
The whole thing runs in your browser. Your image is drawn to a canvas and re-exported locally; it's never uploaded to a server, which means it's fast and your photos stay on your device. You can export as PNG, JPG, or WebP and, for the lossy formats, tune the quality.
It's built for the common resize job: getting a photo down to the right dimensions for a post, a thumbnail, or a share image, without opening Photoshop.
Features at a glance
Resize by pixels or percentage
Set exact target width/height in pixels, or scale by percentage. Choose whichever is more convenient for your workflow.
Lock or unlock aspect ratio
Lock to maintain proportions (default). Unlock when you need exact dimensions regardless of distortion.
Batch resize
Drop multiple images at once. All are resized to the same target dimensions and downloaded as a zip or individual files.
Output format conversion
Resize and convert format in one step — JPG to WebP, PNG to JPG, etc. Often saves significant file size.
Quality control for JPG/WebP
Slider from 1-100 for lossy formats. Live preview shows the quality/size tradeoff.
Preset dimensions for platforms
One-click preset for Instagram post, Twitter header, Facebook cover, YouTube thumbnail, and more. No need to remember the pixel dimensions.
Preview before download
See the resized image at actual size before saving. Compare with original to check quality.
100% browser-based
No uploads, no waiting. Files stay on your device. Safe for personal photos, client work, and sensitive screenshots.
How to use the Image Resizer
- 1
Drop your images
Drag and drop one or more image files (PNG, JPG, JPEG, WebP, GIF, BMP) into the tool. Or click to pick files. The original dimensions appear.
- 2
Set target dimensions
Enter the new width or height in pixels. With aspect ratio locked, the other dimension updates automatically. Or switch to percentage mode.
- 3
Choose output format
Keep the original format or convert — JPG for photos, WebP for modern web (smaller), PNG for graphics with transparency.
- 4
Set quality (for JPG/WebP)
85-95% is usually the sweet spot. Preview shows you the quality/size tradeoff live.
- 5
Click Resize
Images are processed instantly in your browser. Preview and total file size appear immediately.
- 6
Download
Download individual images or a ZIP of all resized files. Ready to use in your CMS, email, or social media.
When to use the Image Resizer
Social media
- →Instagram posts and stories: Posts 1080×1080 (square) or 1080×1350 (portrait). Stories 1080×1920. Use presets to hit exact dimensions without guesswork.
- →Twitter/X images: In-tweet: 1200×675. Header: 1500×500. Profile picture: 400×400. Resize and upload instantly.
- →Facebook and LinkedIn: Facebook cover: 820×312. LinkedIn cover: 1584×396. Profile pictures: 400×400 (FB), 400×400 (LI). Batch-resize when you update branding.
- →YouTube thumbnails: 1280×720 (16:9), at least 1920×1080 for HD. Thumbnails are critical for click-through — resize from your design exports.
- →TikTok and Reels: Vertical 1080×1920 (9:16). Crop and resize your horizontal source videos' frames for thumbnails.
Web development
- →Prepare hero images for responsive sites: Generate multiple sizes (1920w, 1280w, 768w, 320w) for `srcset`. Browsers pick the best one for each device.
- →Create OG and Twitter Card images: Open Graph: 1200×630. Twitter summary card: 1200×600. Resize your design mockups or screenshots to meet these dimensions.
- →Compress photos before upload to CMS: CMS storage and bandwidth costs less when images are the right size. Resize large phone camera photos (~5 MB each) down to ~200 KB before uploading.
- →Create app icons: iOS: 180×180. Android: 512×512 adaptive. Web favicon: multiple sizes. Batch-resize from a single high-res source.
Ecommerce
- →Resize product photos for marketplaces: Amazon: 2000×2000 recommended. Shopify: max 4472×4472. Etsy: 2700×2025. Consistent dimensions across listings signal professionalism.
- →Batch-process new inventory: Drop 50 product photos, resize to spec, download all at once. Saves hours of manual work.
- →Generate thumbnails automatically: Keep full-resolution originals + generate small thumbnails (200×200 or 400×400) for category pages.
Personal and professional
- →Shrink photos for email: 10 MB photo from a phone becomes a 200 KB email attachment. Easier for recipients to download.
- →Screenshots for bug reports: High-DPI screenshots are huge. Resize to 1200w for GitHub issues and support tickets.
- →Resume and portfolio photos: Headshot usually 400×400 or 800×800 for professional profiles.
- →Print vs web: Print needs 300 DPI; web needs 72 DPI. Resize pixel dimensions, and convert with quality balance.
Worked examples
Shrink phone photo for web
4032×3024 iPhone photo → 1200×900 for blog.
Original: 4032×3024 (8 MB JPG) Target: 1200×900 (aspect locked) Format: JPG quality 85
Resized: 1200×900 File size: 180 KB (44× smaller) Quality: visually indistinguishable
Instagram post resize
Desktop design mockup → 1080×1080 square.
Original: 1920×1920 Target: 1080×1080
Resized: 1080×1080 Format: PNG (keeps quality) File size: 450 KB
Batch resize 20 product photos
Ecommerce upload ready.
20 photos, various sizes Target: longest side = 2000, Amazon-ready Format: JPG quality 90
All 20 resized in 4 seconds Total download: 15 MB (vs 180 MB originals) Ready for Amazon listings
Convert PNG screenshot to WebP
5× smaller file, same visual.
Original: screenshot.png (2.1 MB, 1920×1080) Target: convert to WebP, same dimensions Quality: 85
Output: screenshot.webp (380 KB, 1920×1080) File size: 5.5× smaller
Generate thumbnails
Product image at multiple sizes.
Source: 2400×2400 product photo Generate: 600×600, 300×300, 150×150 Format: WebP quality 85
3 output files: - 600×600 (120 KB) - 300×300 (40 KB) - 150×150 (15 KB)
Fit to box with aspect preserved
Longest side 1920, aspect ratio maintained.
Source: 3840×2160 (16:9) Fit to box: 1920 longest side
Output: 1920×1080 (aspect kept)
Under the hood
Resizing is done with the HTML canvas API. The image is drawn into a canvas at your target dimensions with high-quality image smoothing enabled, then exported with canvas.toDataURL at your chosen format and quality. Because it re-encodes the pixels, the output is a fresh image — EXIF metadata, color profiles, and the original file's encoding are not carried over.
Quality only applies to lossy formats. For JPG and WebP the quality slider maps to the encoder's quality setting; for PNG it has no effect, since PNG is lossless. The result size shown is estimated from the encoded data length, so it's a close approximation rather than the exact byte count of the saved file.
Downscaling (making an image smaller) looks great. Upscaling (entering dimensions larger than the original) will stretch the existing pixels — the browser interpolates, but it can't invent detail that isn't there, so enlarged images look soft. Everything is client-side; nothing leaves your browser.
Common problems and solutions
⚠Upscaling can't add detail
Entering dimensions larger than the original stretches the existing pixels. The browser interpolates, but the result looks soft and blurry — there's no detail to recover. Resize down, not up, for best results.
⚠Metadata is stripped
Re-encoding drops EXIF data (camera info, GPS, orientation) and color profiles. That's good for privacy but means orientation tags won't carry over — a photo may appear rotated if it relied on an EXIF orientation flag.
⚠PNG ignores the quality slider
PNG is lossless, so the quality setting does nothing for it. To make a photo smaller, export as JPG or WebP where quality actually reduces file size.
⚠Resizing to JPG flattens transparency
JPG has no alpha channel. If your source is a transparent PNG and you export as JPG, transparent areas fill with a background color. Keep PNG or use WebP to preserve transparency.
⚠Large images use memory
Very large source images (like 4K+ photos) are held in the browser as canvas pixels, which can be memory-heavy on low-end devices. It's one image at a time, not a batch processor.
How it compares
Desktop editors like Photoshop or GIMP give you resampling algorithms, sharpening after downscale, and batch processing. A canvas-based tool like this trades that control for speed and privacy: no upload, no install, instant result for one image at a time. For a quick single resize to a known size, that's usually the better tradeoff.
For serious photo work, or when you need to resize hundreds of files, batch upscaling with AI, or precise resampling control, a dedicated editor or a command-line tool like ImageMagick is the right choice. This is the grab-it-and-go option for web-sized images.
Questions and answers
▶Are my images uploaded anywhere?
No. Resizing happens entirely in your browser using the canvas API. The image never leaves your device, which is why it's fast and private.
▶How do I resize without distorting the image?
Keep 'Maintain aspect ratio' checked (it's on by default). Then set either width or height and the other adjusts automatically to preserve the proportions, so the image isn't stretched.
▶Which format should I export?
Use JPG for photos where small size matters, PNG when you need lossless quality or transparency, and WebP for the best size-to-quality balance on modern browsers. For lossy formats, adjust the quality slider.
▶Why does my enlarged image look blurry?
Because upscaling can't create detail that wasn't captured. The tool interpolates existing pixels, which softens the result. For sharp output, resize down from a larger original rather than enlarging a small one.
▶Can I resize multiple images at once?
No, it handles one image at a time. For batch resizing, use a desktop tool like ImageMagick or an image editor with batch processing.
Additional resources
- HTML Canvas API — MDN — Browser image manipulation API used by this tool.
- Responsive Images — MDN — How to use srcset and sizes for multi-resolution images.
- Image Optimization — Web.dev — Google's guide to image optimization for page performance.
- Social Media Image Size Guide — Current dimensions for every social platform.
- Image Optimization Blog — Tooleras — Our guide to image resizing best practices.
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