Resize Images Online — Free Image Resizer

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.

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.

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.

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.

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.

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.

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.

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.

Leave the aspect lock on, or pick a fit mode that respects the ratio. Type one dimension and the other follows automatically. If you need to hit an exact box whose shape differs from your photo, Cover fills the box and trims the overflow, while Contain fits the whole image inside and leaves space. Stretch is the only mode that distorts, and it exists for the rare case where you genuinely want that.

Resizing changes how many pixels there are. Cropping changes which pixels you keep. Resizing a 4000x3000 photo to 1000x750 keeps the whole frame at a quarter of the width, and cropping to 1000x750 takes a rectangle out of the middle at full detail. If your target is a different shape from your source, you need both, which is what Cover mode does in one pass.

Making it smaller, barely. The browser resamples with high-quality filtering, so a well-lit photo scaled down usually looks sharper than the original did at that size. Two things do cost you. Every non-PNG output is re-encoded, at quality 90 by default, so a JPEG picks up one more generation of loss. And scaling up invents pixels it cannot know, which is what the upscaler exists for.

The presets have the current numbers so you don't have to memorize them. Instagram takes 1080x1080 square, 1080x1350 portrait and 1080x1920 for a story or reel. A YouTube thumbnail is 1280x720 and a channel banner is 2560x1440. LinkedIn posts are 1200x627 and X posts 1200x675. Pinterest wants a tall 1000x1500. Fifteen presets ship in total, one click each.

Not with this tool, and that's the honest answer. A resizer interpolates between the pixels you already have, so scaling a 500 pixel image to 2000 gives you a soft 2000 pixel image. Our upscaler runs a Real-ESRGAN model that reconstructs plausible detail instead of interpolating, which is a genuinely different operation. Use the resizer to go down and the upscaler to go up.

Yes, up to 10 files and 50 MB per batch. Drop them all in, set the dimensions or pick a preset once, and every file is processed with those settings, then downloaded individually or as one ZIP. Mixed orientations are worth a thought first: a portrait and a landscape sent to the same fixed box will be trimmed differently under Cover, so run them separately if the framing matters.