哪些版本的 IE 支持 PNG 图标? [英] Which versions of IE support PNG favicons?

问题描述

指向一篇名为 包含以下代码段:

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"请注意，.ico 以外的图像格式的快捷方式图标 — 对于例如，.bmp、.gif 或 .png — 无法在 Internet 中显示探索者."

一些非官方来源的引述:

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首先，IE 需要一个实际的图标文件.不仅仅是重命名的 jpg 或 png带有 ico 扩展." - Greg Hostetler, 在 IE7 中设置 Favicon..

"它必须是windows图标格式而不是PNG或GiF，IE8只是支持 ICO." - xyberbit，MSDN..

另一方面，Internet Explorer 不支持 PNG 图标，但它会忽略 PNG 图标并使用 ICO 图标，不管它们的声明顺序." - Jonathon T.Neal.

"一.大.问题.IE10不支持条件注释,而且不支持 PNG 图标." - Jonathon T.Neal

回答其他查询:

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我可以将文件类型从 .png 重命名为 .ico，反之亦然解决这个不兼容问题?

遗憾的是没有(由@Truerror 在 2013 年 17 月 6 日在 IE10 中测试).IE10 及更早版本需要实际的图标 (.ico) 文件.

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应该是 16x16 .ico 吗?

微软> 不得不说:

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"考虑创建一个 16x16 像素的图标和一个 32x32 像素的图标图标(和更大，带宽允许)，因为在高 DPI 显示器上，Internet Explorer 可能会拉伸图标以适应可用空间."

In this old StackOverflow post, it was said that only IE6 had issues with PNG favicons, but on channel9, it said that IE7 also does not support PNG favicons either.

But, unfortunately, the channel9 link has been deleted - so does anyone know the official/tested information that states which version of IE started to support PNG favicons?

解决方案

The short answer:

IE11 is the first version of Internet Explorer to support the direct usage of .png and .gif file format favicons.

Why the confusion?

As you mentioned, some seem to have implied that .png favicons are supported in IE7+, while others have stated the opposite.

I believe the confusion is caused by the fact that .png images can be used inside .ico files (.ico files are just image container files after all) as of IE7, which is true .

However, previously, direct .png favicons were only ever compatible with the other major browsers (Chrome, Firefox etc).

Proof of direct .png Favicon compatibility in IE11 and beyond:

The File Format support section on the Favicon wikipedia page resembles the following:

[20] points to an article called Fun with Favicons written by Eric Law, an ex-Microsoft employee and 2013 Microsoft MVP.

The article includes the following:

IE11 shows some significant improvements in Favicon support:

• Favicons may be changed dynamically using script.
• The Favicon URL may point directly at a GIF file.
• The Favicon URL may point directly at a PNG file.

Note though, that it may not be the best idea to use direct .png favicons due to compatibility issues with older versions of IE, as mentioned by Eric in the same blog post:

"Of course, just because you can point at a .png or .gif doesn't mean you should-- for both compatibility and experience reasons (remember .ico can hold multiple image sizes to best suit the display context) you should continue to use a .ico as your favicon."

Another article written by Mr.Law, called IE11 Changes, also briefly mentions IE11's support for direct .png and .gif file format favicons.

Proof of .png Favicon incompatibility in IE10 and before:

There are many official and non official sources proving that IE10 and before only support .ico Favicons.

As of 13/10/2013, the 'file format support' section of the Favicon Wikipedia page resembles the following:

A 2012 article on MSDN called How to Add a Shortcut Icon to a Web Page contains the following snippet:

"Note that shortcut icons in image formats other than .ico — for instance, .bmp, .gif, or .png — cannot be displayed in Internet Explorer."

A few quotes from non-official sources:

"First, IE requires an actual icon file. Not just a jpg or png renamed with an ico extension." - Greg Hostetler, Setting up Favicons in IE7..

"It must be windows icon format instead of PNG or GiF, IE8 just supports ICO." - xyberbit, MSDN..

"On the other hand, Internet Explorer does not support PNG favicons, but it will ignore the PNG favicon and use the ICO favicon, regardless of the order in which they are declared." - Jonathon T.Neal.

"One. Big. Problem. IE10 does not support conditional comments, and it does not support PNG favicons." - Jonathon T.Neal

Other queries answered:

Can I just re-name the filetype from .png to .ico and vice-versa to get around this incompatibility issue?

Sadly not (tested by @Truerror on the 17/06/2013 in IE10). IE10 and before requires an actual icon (.ico) file.

Should it be an 16x16 .ico?

Here's what Microsoft have to say about that:

"Consider creating both a 16x16-pixel icon as well as a 32x32-pixel icon (and larger, bandwidth permitting), since on high-DPI displays, Internet Explorer may stretch the icon to fit the available space."

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