On Mon, Apr 22, 2013 at 6:30 AM, Mathias Schindler <
[email protected]> wrote:

> Which one is larger (given an empty cache)? One single big file
> containing the thumbnails or one small HTML file and individual
> thumbnail files (that includes possible overhead in the TCP/IP
> packages for both scenarios)?
>

For very small images, HTTP headers can indeed overwhelm the actual data;
that's why we use embedded data URIs in styles a lot, which tend to have
very small icons and such.

For typical photo thumbnails there's less relative overhead, but it's still
a bunch of extra files to fetch.

There are a couple disadvantages to using data URIs for largish inline
images such as photo thumbs though:

* browser can't render all the text layout before downloading the images;
images are forced to load at their inline positions.
* increased memory usage -- DOM is going to contain the full base64 data
URI, whereas a separate image file would only store a small link and go
into disk cache. This may be an issue on memory-constrained devices such as
smartphones and tablets.
* I'm not actually sure how disk caching works with data URIs. :) They may
just eat up RAM as long as the page is opened, even when not shown
onnscreen.

I love the idea of using more compact image formats when available, but
doing the negotiating makes things more complicated. Maybe edge-side
includes can rig something up, maybe their overhead would kill the cache
servers. Dunno. :)

Another possibility is to preferably load images on view/section expansion
via JavaScript, which can potentially give you a chance to query the format
compatibility in client JS and avoid any HTTP-level negotiation. (And also
doesn't load any images until you need them.) Things to think about...

-- brion
_______________________________________________
Wikitech-l mailing list
[email protected]
https://lists.wikimedia.org/mailman/listinfo/wikitech-l

Reply via email to