离线 · 无上传 · 浏览器本地完成Offline · no uploads · runs in the browser

BMP 转 Markdown——离线、一行内联、字节原样BMP to Markdown offline — one inline tag, raw bytes

两步：`bmp>html` 把文件的原始字节编成 data URI 放进一个 `<img>`（`alt` 与 `title` 是文件名主干，去扩展名、无名时 `converted`，并做属性转义），`html>md` 再用 Turndown 序列化。实测产物是**一行图片语法**：`body` 里只有那张 `<img>`，样式表在 `<head>` 而序列化只取 `body`，CSS 不会漏进 `.md`；`data:` 前缀是 `image/bmp`（类型被浏览器认出的时候——从 ZIP 解包的文件不带类型，前缀会变成 `application/octet-stream`）。这一路**不重编码、不降尺寸**，所以像素逐字节是你原来那一份。代价有两条，都要说在前面：一，BMP 常常完全不做压缩，再乘上 base64 的 4/3，`.md` 会相当大、而且整段负载挤在同一行里，审阅与 diff 都不友好——真要提交进仓库的文档，外链是更好的形状；二，**显示由阅读器决定**，BMP 的 `data:` 图片在不少 Markdown 阅读器与托管站上并不显示，那种场合请自己写 `` 并把图放在同一目录。想要变小的 BMP 出口通常是 BMP→PDF（图像流压缩存放，幅度看内容，而且那一路会先铺白底）；想要能被到处接受的位图，就走 BMP→PNG / JPG / WebP 那几页重编码。全程只有 storage 权限，不联网。Two steps: `bmp>html` encodes the file’s raw bytes into a data URI inside one `<img>` (`alt` and `title` carry the basename of your file, extension dropped, `converted` when there is no usable name, escaped for attribute position), and `html>md` then serialises it with Turndown. Measured, the artifact is **one line of image syntax**: the `<img>` is all the body holds, the stylesheet sits in `<head>` and the serialisation reads only the body, so no CSS leaks in; the `data:` prefix is `image/bmp` when the browser recognised the type — a file unpacked from a ZIP has none, and its prefix becomes `application/octet-stream`. This route does **not re-encode or downscale**, so the pixels are byte-for-byte the ones you had. State the two costs up front. First, BMPs are usually uncompressed, and base64 multiplies that by 4/3, so the `.md` gets hefty and the whole payload sits on a single line that is hostile to review and diffs — for documents that go into a repository, an external reference is the better shape. Second, **display is the reader’s decision**: a BMP `data:` picture does not render in many Markdown readers and hosting sites, so write `` and keep the file alongside when it has to show. For a BMP exit that actually gets smaller there is BMP to PDF, which stores the image stream compressed; for a bitmap everybody accepts, take the re-encoding pages — BMP to PNG, JPG or WebP. All of it on the storage permission, with no network at all.