图片格式转换

UpBox优盒工具箱，免费图片格式转换工具，JPG、PNG、WebP 互转，画质可调，透明背景按格式保留，本地处理不上传。

无需注册 · 数据不上传No sign-up · nothing uploaded

选择图片Choose an image

点击选择或拖入图片Click to choose or drop an image 支持 JPG、PNG、WebP，图片不会上传JPG, PNG and WebP — nothing is uploaded

— 选择图片后即可转换

输出格式Output format

画质Quality92%

PNG 无损、保留透明；JPG 不支持透明，会填成白色；WebP 兼顾两者。PNG is lossless and keeps transparency; JPG fills transparency with white; WebP does both.

预览与下载Preview

选择图片后即可转换

原始大小—

转换后—

体积变化—

输出格式—

选择图片后即可转换

下载图片

本工具所有运算在本地浏览器完成，你的文件、文本不会上传到服务器

工具介绍

图片格式转换在浏览器里完成：读入一张图片，选择 JPG、PNG 或 WebP，再按需要调整画质。图片不上传，也没有网络请求。 Conversion happens in your browser: load an image, pick JPG, PNG or WebP, and adjust quality if needed. Nothing is uploaded and no request is made.

转换会保留原始像素尺寸，不额外缩放。PNG 无损并保留透明；JPG 不支持透明，透明区域会填成白色；WebP 体积更小，同时支持透明。 Pixel dimensions are preserved without extra resizing. PNG is lossless and keeps transparency; JPG fills transparent areas with white; WebP is smaller and still supports transparency.

本地转换不上传Runs locally, no upload
JPG / PNG / WebP 互转JPG, PNG and WebP
画质可调Adjustable quality
保留原始像素尺寸Keeps pixel dimensions
透明背景按格式处理Transparency handled per format

使用说明

选择或拖入一张图片，右侧会显示尺寸与当前体积。Choose or drop an image; its dimensions and size appear on the right.
在“输出格式”里选择目标格式，JPG / WebP 可继续调画质。Pick a target format; JPG and WebP also let you tune quality.
点“转换格式”，页面会显示转换后的体积与变化比例。Press Convert to see the new file size and the change.
点“下载图片”保存，文件名会带上 `-converted`。Download the result; the filename gains a `-converted` suffix.

常见问题

转换会改变分辨率吗？Does conversion change resolution?

不会。画布按原图宽高建立，只改变编码格式与画质，像素尺寸保持不变。No. The canvas matches the original width and height; only the encoding and quality change.

为什么转成 JPG 后透明背景变白了？Why did transparency turn white in JPG?

JPG 格式本身不支持透明通道，透明区域只能填成白色。需要透明请选 PNG 或 WebP。JPG has no alpha channel, so transparent areas become white. Use PNG or WebP to keep transparency.

转成 WebP 一定更小吗？Is WebP always smaller?

多数照片在同画质下更小，但简单图形或已压缩的小图可能差不多，甚至略大；页面会直接显示变化比例。Usually smaller for photos at the same quality, but simple graphics or tiny files may stay similar or grow; the page shows the exact change.

支持批量转换吗？Can it convert several images at once?

当前一次一张。需要批量时，可逐张转换，或先用图片压缩工具统一处理尺寸。One image per run. For batches, convert one by one or resize them first with the compressor.