When all the picture vs srcset started showing up on twitter, I was initially
behind picture. I'm sure you all know the arguments for it, and I liked those
arguments. Today though, I was reading an article about the two, and there was
a misunderstanding about how srcset was working in the comments, and it made me
realize that something closer to srcset would be ideal.
The big thing I realized is that as a developer, I do not want to write more
media queries - or anything that works at all like them - into image elements.
It's redundant. There's a good chance there's already a bunch of CSS in place
controlling the shape and size of the image element itself, why should I have
to write a bunch more, somewhere else, to control the src of the image too?
Why can't it work so that in the html I say here's an image, there's a version
of it at 150x150, and a version at 48x48, and then in the CSS I say that the
image is 25% of the width of the article it's in, which works out to 100px
wide, and then the browser can just decide that the 150x150 would be best, and
scale it down. If I change the CSS, I don't have to change the html too, the
images I provided are still only available at those sizes. With image/picture
sources set by viewport dimensions, even something as simple as adding more
padding around articles on a site could involve going through all the HTML and
adjusting the breakpoints in the tags. This way layout, units, and screen dpi,
don't matter when writing the HTML,
I've seen people get confused and think srcset work this way, instead of by
viewport size (unless I'm the confused one), and if they were right then srcset
would work well for this. It would be even nicer if there was something even
more CMS friendly, like:
<img src="/img/people.jpg" sizes="100x200 300x250 900x300"
pattern="/tools/resizer.php?img=people.jpg&width={w}&height={h}" alt="A
picture of some people.">
So src would be the fallback, then sizes would say which dimensions are
available, in a fairly common format, using spaces to separate options like
class does. pattern (probably a bad name) would be a template for the URL the
browser can request the image from, replacing {w} and {h} with the requested
dimensions. There wouldn't need to be a token for the dpi/resoultion/whatever,
the browser could just request an image twice or three times or whatever the
size. There's no point in having sizes="100x100@1 100x100@2 200x200@1" when you
can just have sizes="100x100 200x200"
This gives the designer/developer full control over the shape and size of the
image element (through CSS), while still allowing the browser to make decisions
based on bandwidth and whatnot.
--
Mike Gossmann | [email protected] | http://gossmati.ca
