Resize Image
Change an image's width and height to exact dimensions online for free.
How to use / 使用步骤
- Upload your image.上传图片。
- Enter a target width or height; keep the aspect-ratio box ticked to scale proportionally.输入目标宽度或高度，勾选「保持比例」可等比缩放。
- Click apply and download.点击应用并下载。
About Resize Image / 关于本工具
Resizing changes an image's pixel dimensions — its width and height — which is different from compression (changing file size at the same dimensions). You resize to fit a photo into a layout, meet an upload's maximum dimensions, make a thumbnail, or shrink a huge camera image that's far larger than any screen needs. This tool lets you set an exact width or height and, with aspect ratio locked, calculates the other side automatically so the image never looks stretched.
调整尺寸改变的是图片的像素宽高，这和压缩（在尺寸不变的前提下改变文件体积）不同。你会因为要把照片塞进版式、满足上传的最大尺寸、做缩略图，或缩小一张远超任何屏幕所需的巨幅相机图而调整尺寸。本工具让你设定精确的宽或高，并在锁定比例时自动算出另一边，图片绝不会被拉变形。
Downscaling vs upscaling / 缩小与放大
Making an image smaller is safe and usually improves sharpness for its new size. Making it larger can't invent detail that wasn't captured, so an upscaled image looks soft or blocky — start from the highest-resolution original you have whenever you need something bigger. Resize first, then compress if you also need a smaller file.
把图片改小是安全的，通常还会让它在新尺寸下更锐利。放大则无法凭空造出未曾拍下的细节，于是放大后的图会发虚或发糊——需要更大的图时，尽量从你手头分辨率最高的原图出发。先调整尺寸，若还需更小的文件再压缩。