Html Gmail 中未显示 Base64 编码的图像
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Base64 encoded image is not showing in gmail
提问by Harikrishnan
I have an embedded HTML email in which I'm using a base64encoded image. Image doesn't show in gmail when accessing via chrome. But it works fine when accessing same mail via mail client(Mail application on Mac). I have set headers correctly. Any idea?
我有一个嵌入的 HTML 电子邮件，我在其中使用了base64编码图像。通过 chrome 访问时，图像不显示在 gmail 中。但是当通过邮件客户端（Mac 上的邮件应用程序）访问相同的邮件时它工作正常。我已正确设置标题。任何的想法？
My code
我的代码
<html>
<body>Hi
<img src="data:image/png;base64,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" width="273" height="11" alt="">
</body>
</html>
Headers
标题
Content-Type: text/html; charset=utf-8
Content-Transfer-Encoding: quoted-printable
回答by Ted Goas
base64 encoded images are not well supported in email.They aren't supported in most web email clients (including Gmail) and are completely blocked in Outlook. Apple Mail is one of the few clients that doessupport them, that's why you're able to see them there but not elsewhere.
电子邮件中不支持 base64 编码的图像。大多数网络电子邮件客户端（包括 Gmail）不支持它们，并且在 Outlook 中被完全阻止。苹果公司的邮件是为数不多的一个客户不支持他们，这就是为什么你能看到他们有，但不是在其他地方。
Another thing to be mindful of with base64 encoded images is email file size. Gmail App (iOS, Android) and Outlook (iOS) truncate email messages whose file size exceeds 102KB. Remotely referenced images (Eg. <img src="http://www.website.com/image.png">do not count towards the email's file size, but base64 encoded images doand can quickly blow out an email's file size past the 102KB limit. Just something else to consider.
使用 base64 编码图像要注意的另一件事是电子邮件文件大小。Gmail 应用程序（iOS、Android）和 Outlook (iOS) 会截断文件大小超过 102KB 的电子邮件。远程引用的图像（例如<img src="http://www.website.com/image.png">，不计入电子邮件的文件大小，但 base64 编码的图像可以并且可以迅速使电子邮件的文件大小超过 102KB 限制。只是需要考虑的其他事项。
回答by Kamil Kie?czewski
It looks like that direct encoded images (non-bease64 ) are also not supported by gmail :( - I write below snippet to convert image from base64 to direct form and send it in email - but still not see any image :( . To solve this issue you need to add images as attachements with cid and use that cid in img tags <img src="cid:123456">- more details here
看起来 gmail 也不支持直接编码的图像（非 bease64 ）:( - 我写下面的代码片段将图像从 base64 转换为直接形式并通过电子邮件发送 - 但仍然看不到任何图像:(。要解决这个问题你需要添加图像作为带有 cid 的附件并在 img 标签中使用该 cid <img src="cid:123456">- 更多细节在这里
function convert() {
let base64 = imageBase64.value.split('base64,')[1];
let hex = [...atob(base64)].map(c => c.charCodeAt(0).toString(16).padStart(2, 0));
let img = 'data:image/png,%' + hex.join('%');
pic.src = img;
msg.innerText = img;
}Put your img base64 data uri here<br>
<input style="width:200px" id='imageBase64' value="data:image/bmp;base64,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">
<button onclick="convert()">Convert</button><br> Result
<br>
<textarea id='msg' rows="4" cols="50"></textarea><br>
<img id='pic'>