Why is my screenshot so much smaller as JPG?

PNG is lossless and uncompressed for photographic content. A 1080p screenshot is often 1–3 MB as PNG, 100–300 KB as JPG at quality 90 — typically 5–10× smaller with no visible difference.

What happens to transparent pixels?

JPG has no alpha channel. Transparent pixels are flattened to white before encoding. If you need to keep transparency, convert to WebP instead.

Is there quality loss?

Yes — JPG is lossy. At quality 90 the difference is invisible at normal viewing distance. At quality 75 you may see mild softening on fine text and hard edges, but the file is much smaller.

Best quality for email attachments?

Quality 80–85 hits a sweet spot for email: still sharp, under 500 KB for most photos, well within attachment limits.

PNG转JPG转换器——缩小截图和照片

将PNG转换为JPG，并在不需要透明度时×将文件大小裁剪5–10倍。EXIF 自动定向，透明像素被压平成白色，质量滑块。

请上传PNG图片或点击浏览

关于PNG转JPG

PNG 是无损且支持透明度的，这使得它成为 UI 资产和设计工作的合适选择。对于上传、发送或展示在页面上的照片和截图，JPG体积明显更小——通常比同等的PNG小5到10×。该工具在服务器端解码PNG，将透明像素压平为白色（JPG没有alpha通道），并以你选择的质量重新编码。默认为90质量;为了方便发邮件，尺寸降到75。