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Feedback on Image modules

From: Anthony Ricaud <anthony@ricaud.me>
Date: Sat, 11 Dec 2010 20:50:01 +0100
Message-Id: <A173967A-D100-41E2-8554-732EEBF87339@ricaud.me>
To: www-style list <www-style@w3.org>

In the image() notation, there is a mechanism to avoid downloading images before knowing it won't be able to render it.

> If the URL for the image ends in a file extension (a period followed by letters) of four ascii letters ([a-zA-Z]) or less, then the UA may skip trying to load images whose file extension matches an image format it knows it does not support. For example, a UA that knows it supports JPEG and GIF, but expects to encounter many PNG and SVG images may choose to skip over images with filenames ending in ‘.png’ or ‘.svg’ without loading them to check their MIME type. However it must not skip over images with filenames ending in extensions it doesn't recognize.

This means that when UAs start implementing this, they'll need to check for a list of all existing image formats they don't support. And when a new format will come out, every UA will download this new format since it knows nothing about it. 

Plus, it ties the URL to the file format which is not a good idea.

Wouldn't it make more sense to use the same logic as @font-face : format() ? Only known formats are downloaded.
Received on Saturday, 11 December 2010 22:22:28 UTC

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