Resize Images Online — Free Image Resizer
Resize JPG, PNG, WebP, and AVIF images to exact dimensions or scale by percentage. Bulk resize for websites, social media, or email — without uploading a single file.
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How to Resize Images
Select your images
Choose files or drag and drop them into the resizer. Supports JPG, PNG, WebP, AVIF, and GIF.
Set dimensions
Enter target width and height in pixels, or scale by percentage. Lock the aspect ratio to prevent distortion.
Download
Download the resized images individually or all at once as a ZIP file.
Social Media Image Sizes (2026)
Use these recommended dimensions to ensure your images display perfectly on every platform. Incorrectly sized images get cropped, compressed, or displayed at lower quality by social media platforms.
| Platform | Type | Dimensions (px) |
|---|---|---|
| Square Post | 1080 × 1080 | |
| Portrait Post | 1080 × 1350 | |
| Story / Reel | 1080 × 1920 | |
| Landscape | 1080 × 566 | |
| Post | 1200 × 630 | |
| Cover Photo | 1640 × 624 | |
| Story | 1080 × 1920 | |
| YouTube | Thumbnail | 1280 × 720 |
| Channel Banner | 2560 × 1440 | |
| X / Twitter | Post Image | 1200 × 675 |
| Header | 1500 × 500 | |
| Post | 1200 × 627 | |
| Cover Photo | 1584 × 396 | |
| TikTok | Video Cover | 1080 × 1920 |
| Pin | 1000 × 1500 |
Why Resize with LeanImg?
Oversized images slow down websites, get rejected by email providers, and display poorly on social media. Resizing to the correct dimensions improves page load speed, reduces bandwidth costs, and ensures your images look sharp on every platform. Google uses page speed as a ranking signal, so properly sized images directly improve SEO performance. LeanImg resizes images entirely in your browser — your files never leave your device. Need smaller file sizes too? Pair resizing with our Image Compressor for the best results. Or convert between formats like JPG, PNG, WebP, and AVIF.
Pixel-Perfect Dimensions
Resize images to exact pixel dimensions for social media, websites, or print. Aspect ratio lock prevents distortion.
Batch Resize
Resize up to 10 images at once with the same settings. Download individually or as a ZIP.
No Software to Install
Resize images online in seconds. No downloads, no sign-ups — just drag, drop, and go.
Frequently Asked Questions
How do I resize an image without losing quality?
LeanImg uses high-quality interpolation when resizing your images. For best results, avoid enlarging images beyond their original dimensions — downscaling preserves quality much better than upscaling. Enable the "Do not enlarge" option to prevent quality loss from stretching small images. Use a quality setting of 85–95% for the optimal balance between file size and visual fidelity.
How do I resize an image for Instagram?
Instagram recommends 1080×1080 pixels for square posts, 1080×1350 for portrait posts (best engagement), and 1080×1920 for Stories and Reels. Upload your image to LeanImg, enter the target dimensions, and download the resized version. All processing happens in your browser — your photos never leave your device.
Can I resize multiple images at once?
Yes. LeanImg supports batch resizing — select up to 10 images at a time and resize them all with the same dimensions. Once resized, download them individually or all at once as a ZIP file. Batch resize runs entirely in your browser with no upload required.
How do I resize an image to a specific file size (KB)?
To reduce an image to a specific file size like 100 KB or 200 KB, first resize it to smaller dimensions, then use our Image Compressor to fine-tune the file size. Reducing dimensions is the most effective way to decrease file size — a 1080px-wide image is typically 60–80% smaller than a 4000px original.
How do I resize an image on iPhone or Mac?
Open LeanImg in Safari or any browser on your iPhone, iPad, or Mac. Select your image, set the target dimensions, and tap Resize. The tool works entirely in your browser — no app installation needed. Your images stay on your device throughout the process.
What is the best image size for a website?
For most websites, images should be 1200–1600 pixels wide for full-width hero images, 800–1000 pixels for content images, and 300–400 pixels for thumbnails. Pair resizing with compression (JPEG quality 75–85 or WebP) to keep pages fast. Google uses page speed as a ranking signal, so optimized images directly improve SEO.
What is the difference between resizing by pixels and percentage?
Resizing by pixels sets exact output dimensions (e.g., 1080×1080 for Instagram). Resizing by percentage scales the image relative to its original size (e.g., 50% makes a 4000×3000 image become 2000×1500). Use pixels when you need exact dimensions; use percentage when you want to reduce image size proportionally.
Does resizing change the file format?
By default, LeanImg keeps the same format as your original image. A JPEG stays JPEG, a PNG stays PNG. If you need to change the format (e.g., PNG to WebP for smaller files), use our Image Converter after resizing.
Have more questions? Learn more about LeanImg and how we process your images.
Need smaller file sizes? Compress your images after resizing for optimal web performance. Or convert between formats like JPG, PNG, WebP, and AVIF.