Hi List,

This week's "Links for light reading" contains references to image
supplement techniques, in particular, the discussion of the <picture>
element and other alternatives to <img src=....>.

One thing that perplexes me somewhat, is the lack of consideration for an
already existing technology, ie: progressive-images.

Most image formats, including the common web formats (jpg, gif, png),
already support progressive image download, but I rarely see it used.  The
nice thing about progressive images, is that they already solve the
limited-bandwidth problem.

The nice thing about using progressive images, is that even when a browser
doesn't show the partial-image, they will still the final image -> so as
method to handle an already-existing-userbase, a simple browser upgrade is
all that is needed... without changing any spec whatsoever.  And without
any javascript shims, even for MSIE6.

Interestingly, as part of the browser support, a browser could choose to
only download the required partial-image, before choosing to abort the
remainder of the download. In fact, using http-pipelining, a browser/server
combo could optimise the connection, simply based on the download-rate, ie:
fetch all images through the single pipeline, with the server sending only
the first block of each image.  And by extension, a browser/server-pipeline
could even use range requests to indicate which part of the image was not
downloaded, on the low-bandwidth connection, once a high-bandwidth
connection becomes available (which would also help solve the intermittent
bandwidth problem suffered by mobile devices).

Relatedly, a browser could choose to optimise it rendering engine so that
low-zoom levels, it only renders sufficient pixels to match its screen
resolution, to minimise CPU usage. As you zoom in, the browser (possibly
having not fetched the high-detail section of an image, could then
range-request the next image size), could render the higher resolution

I am interested to hear what that list thinks about the proposed <picture>
element (I not a fan... it attempts to replace existing functionality, with
something technically less capable), image replacement techniques using say
javascript/php/etc., or just using existing functionality already built in
(and already backwards compatible).

Note that I had not been able find anything about this anywhere, since the
first proposal for the <picture> element...  That said, todays' google foo
did bring up some links, with this months' date even!.

Mathew Robertson

List Guidelines: http://webstandardsgroup.org/mail/guidelines.cfm
Unsubscribe: http://webstandardsgroup.org/join/unsubscribe.cfm
Help: memberh...@webstandardsgroup.org

Reply via email to