调整大小 图片
更改图像尺寸。比例将自动保留。
将您的图像拖到此处
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尺寸 (px)
留空一个字段以保持比例。
Presets
Free Image Resizer Online — Resize Images in Pixels or Percentage
Change your image dimensions precisely: enter exact pixel values or a percentage scale, lock the aspect ratio to avoid distortion, and download instantly. Supports JPG, PNG and WebP.
Resize options explained
Pixel mode: enter exact target width and height in pixels. Enable the aspect ratio lock to automatically calculate the height when you enter the width (and vice versa) — this prevents stretching or squashing. Percentage mode: enter 50% to halve dimensions, 200% to double them. Ideal for quick batch resizing without calculating exact pixel values. Fit within dimensions: the image is scaled to fit within your specified maximum dimensions while maintaining aspect ratio — pages cannot exceed the set bounds.
Standard image sizes for common use cases
Profile photos: 400×400 px (Twitter, LinkedIn), 320×320 px (Instagram). Social media posts: 1080×1080 px (Instagram square), 1200×630 px (Facebook/LinkedIn link), 1280×720 px (YouTube thumbnail). Web images: 800-1200 px wide for blog posts, 300 px wide for product thumbnails. Print at 300 DPI: A4 = 2480×3508 px, A5 = 1748×2480 px, Letter = 2550×3300 px. Desktop wallpaper: 1920×1080 (Full HD), 2560×1440 (QHD), 3840×2160 (4K).
Enlarging images: when to use AI upscaling instead
Classical resizing (bicubic interpolation) works well for reducing images. When enlarging beyond 100%, the algorithm must invent pixels it does not have, resulting in blurriness, visible pixelation and soft edges. For quality enlargement, use our AI Upscaler which uses machine learning to reconstruct fine details that classical algorithms cannot.
FAQ
Can I resize an image without losing quality?
Reducing image size is generally lossless for PNG and near-lossless for JPEG. Enlarging images always introduces some quality degradation with classical algorithms — use AI Upscaling for quality enlargement.
How do I resize an image for Instagram?
Square post: 1080×1080 px. Portrait post: 1080×1350 px. Story/Reel: 1080×1920 px. Enable the aspect ratio lock and enter the width — the height will calculate automatically.
Can I resize images in bulk?
Yes. Upload up to 20 images and apply the same resize settings to all. Download as a ZIP archive.
What is DPI and does resizing affect it?
DPI (dots per inch) is the print resolution. For web use, DPI is irrelevant — only pixel dimensions matter. For print, 300 DPI is standard. Our tool changes pixel dimensions; DPI metadata can be set separately.
What formats are supported?
JPG, PNG and WebP as input and output. GIF resizing is not currently supported.
Is there a minimum or maximum output size?
Minimum output is 1×1 pixel. Maximum output is 8000×8000 pixels. For larger dimensions, process the image in your preferred image editor.
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