Image watermark
Add text or logo watermarks in bulk: font size, opacity, rotation, anchor position and tile spacing all adjustable, with a live preview before export.
把图片拖到这里，或点击选择
支持 JPG / PNG / WebP / GIF / BMP，可多选；批量加水印时所有图片使用同一套水印参数
水印设置
点击或拖入一张 Logo（PNG 透明底效果最好）
输出设置
提示：水印会画进图片像素里，导出后无法通过本工具单独去除；原图不会被修改，随时可以重新导出。
实时预览（当前第一张图）
选择图片后，这里会实时显示水印效果
预览时长边会缩到 900 像素以内以保持流畅，字号、Logo、间距按同一比例缩放，位置与比例和导出结果一致。
图片加水印，参数该怎么调？
什么时候该加水印：作品图、证件照、简历附件、报价单、设计稿发到群里或传到公开平台之前，加一行「仅供 XX 使用」的说明性水印，被转发出去时用途和来源一目了然；电商图、摄影作品、设计稿更常见的是防盗图——用半透明的平铺水印铺满整张画面，别人即使裁掉一个角，剩下的部分仍然带着水印，很难干净地二次使用。
字号和透明度怎么选：字号建议取图片宽度的 3%~5%，本工具默认按 4% 自动计算，小图不会被大字号糊住，大图也不会小到看不见；尺寸固定的场景（比如统一成 1200 像素宽的配图）可以取消自动、手动指定 30~120 像素。透明度 30%~50% 是兼顾「看得见」和「不毁图」的区间：只做用途声明时可以低到 20% 左右，防盗图建议 40% 以上，否则抹掉很容易。
平铺只适合防盗图：单个角标裁一下就没了，铺满整张图后才真正起到防护作用。间距 150~300 像素比较平衡，太密会明显影响观感，太疏则可能被人裁掉一块无水印的区域。斜向 30° 左右的平铺水印比水平排布更难规避，也更像常见的水印样式。
图片水印与导出格式：Logo 建议用透明底的 PNG，JPEG 的白底会在深色照片上留下一个个白方块。导出格式上，需要保留透明度或让文字边缘保持锐利的，选 PNG；要发微信、上传到只认 JPG 的平台，选 JPG 并把质量放在 85% 左右；WebP 同画质体积更小，但个别老系统打不开。所有解码、绘制、导出都在你的浏览器里完成，图片不会被上传到任何服务器——可以打开开发者工具的 Network 面板自行确认，断网也能正常使用。
FAQ
No. The watermark is painted straight into the pixels - there is no separate watermark layer to peel off; the semi-transparent tiled style is designed so that removing it is messier than redoing the picture. The good news: the original image is never modified, so when you need a clean version, pick the original again and export.
It encodes exactly once. Choose PNG and it is lossless, at the cost of a larger file; choose JPG or WebP and there is one lossy pass - with quality at 85 percent or above the difference is barely visible to the eye. The tool merges watermarking and exporting to the target format into a single step, one compression round less than compress, then watermark, then compress again.
For smoothness the preview scales the long edge down to at most 900 pixels before drawing, with font size, logo size and tile spacing scaled by the same ratio - so positions and proportions match the export; on screen everything just shows shrunk, so strokes look thinner than at 1:1. Also, JPG and WebP have no transparency: exports get a white underlay, while PNG keeps its transparent areas.
Not directly - browsers cannot decode that format. Run the photo through the HEIC-to-JPG tool on this site first (processed locally in your browser, no upload), then come back here to watermark it.
No. Reading, painting the watermark, format conversion and download all happen on this page through the browser canvas: no upload request, nothing written to a server disk. It still works with the network off, so sensitive pictures - ID photos, contracts, payslips - are safe to process here.