"image/png"和"image/png"有什么区别?和"image/x-png"? [英] What is the difference between "image/png" and "image/x-png"?
问题描述
"image/png"和"image/x-png"有什么区别?
What is the difference between "image/png" and "image/x-png"?
推荐答案
x-
前缀用于非标准MIME类型(即未在IANA中注册).因此,我假设image/x-png
在MIME类型标准化之前就已经是PNG.
The x-
prefix is given to non-standard MIME types (i. e. not registered with IANA). So I assume that image/x-png
would have been PNG before the MIME type was standardized.
6.3.新的内容传输编码
实施者可以在必要时定义私有的Content-Transfer-Encoding值,但必须使用x令牌(以"X-
"为前缀的名称)表示其非标准状态,例如e.例如,"Content-Transfer-Encoding: x-my-new-encoding
".其他标准化的Content-Transfer-Encoding值必须由标准跟踪RFC指定.
这些规范必须满足的要求在 RFC 2048 中给出.
因此,除以下内容外,所有内容传输编码名称空间
以"X-
"开头的内容已明确保留给IETF,以备将来使用
使用.
Implementors may, if necessary, define private Content-Transfer-Encoding values, but must use an x-token, which is a name prefixed by "X-
", to indicate its non-standard status, e. g., "Content-Transfer-Encoding: x-my-new-encoding
". Additional standardized Content-Transfer-Encoding values must be specified by a standards-track RFC.
The requirements such specifications must meet are given in RFC 2048.
As such, all content-transfer-encoding namespace except that
beginning with "X-
" is explicitly reserved to the IETF for future
use.
- RFC 2045 —多用途Internet邮件扩展,第6.3节 >
这也记录在PNG规范中.参见 FalseVinylShrub的答案.
This is also documented in the PNG specification. See FalseVinylShrub's answer.
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