I recall it was long ago best practice to hardcode width and height for any image (generally so it allocated appropriate amount of space while loading), but now with most people on high speed and things generally more dynamic, what is the best practice for this? Is it still preferred that any content image have inline size set with html?
It doesn't matter if you set the size using HTML attributes or in a stylesheet, but you should still specify the size for images.
Eventhough images are loaded a lot faster nowadays, there is still a noticable delay between the page being displayed and the images pop up. It's still irritating when the layout of a page changes while the images are loading.
Yes, it is still preferred.
Plenty of people are not on high speed connections, and mobile is becoming more common.
It doesn't have to be inline - you can do it in external CSS. Some older browsers, if you don't specify the size, will just treat it as 0px;
Its always best to use CSS
You could hardcode the image height and width like this
.myimg img {
width: 10px;
height: 10px;
}
your image file itself should be the size you want it to display as, for the most part, if your concerned about slow loading especially! if you've got a 500X800 px image, that you only want to show as 100X200, scale it down! the file size will be much smaller so it will load faster :)
I would say yes if you want to make sure the white space is included in case of the image does not load or during document load. But no if you're scaling/resizing the image with those attributes, as its unnecessary load on the browser and causes image distortion.
If you are designing for cross browser compatibility, then you should at the very least specify the height and width in your CSS for the image itself. I have found inconsistency between FireFox, IE, Opera, etc if sizes are not specified specifically for the image. Due to the fact that each browser, not to mention different versions, handle adherence to HTML Standards differently. I have found that some browsers will do its best to extrapolate the HTML designers intent, while others just croak on the first error. I would also recommend em sizes, rather than pixel or %'s if you intend for the website to be viewed from a mobile device such as a tablet. I will say, however I have just started playing with HTML5 so I don't of the difference in HTML5 with respect to images.
I just answered a similar question on Wordpress Stack Exchange and also on Webmaster Stack. I am posting it here intending to clarify and help more people. (admins/moderators: if this isn't allowed, let me know the proper way to help).
doesn't really means you need to specify width and height in the html. What it means is that is you gotta reserve te proper space and when the image is loaded, the browser doens't have to reflow and repaint the page.
Besides, if you hardcode the dimensions, it kinds of defeats responsive behaviour. If your layout is not responsive, it's ok, but if you want to keep some responsiveness, you could use only CSS to achieve the results.
Most of time, using both width and max-width:100 will do the work, but this post from Smashing Magazine has an interesting technique: instead of using max-width:100%, you can use The Padding-Bottom Hack :
"With the technique, we define the height as a measure relative to the width. Padding and margin have such intrinsic properties, and we can use them to create aspect ratios for elements that do not have any content in them.
Because padding has this capability, we can set padding-bottom to be relative to the width of an element. If we also set height to be 0, we’ll get what we want. [...]
The next step is to place an image inside the container and make sure it fills up the container. To do this, we need to position the image absolutely inside the container, like so:"
.img-container {
padding-bottom: 56.25%; /* 16:9 ratio */
height: 0;
background-color: black;
}
.img-container img {
position: absolute;
top: 0;
left: 0;
width: 100%;
height: 100%;
}
Related
I use a lot of absolute elements in my website design so that it will mold to whatever browser dimensions are being used, but there is a minimum size that I want to use. In other words, I want my website to become compact as the browser is being resized smaller but at a certain point I want the overflow:auto attribute to kick in and force the user to see the whole page using scrolling instead of compacting the page further.
Any ideas? I tried putting in an empty table with specific dimensions into an element with overflow:auto, but that didn't work. I am not a terribly experienced web-designer.
CSS
html, body {
min-width: 980px;
}
I want to display a collection of image thumbnails in a grid. The images will come in a variety of sizes, but I'd like to restrict the thumbnails to a particular size (let's say 200px wide and 150px tall).
What I'd like to find are some magical HTML markup and CSS rules that will
Allow the images to be included in normal <img> elements
Ensure that the thumbnails fit into their 200x150 pixel box, retain their proportions, and are centered in whichever dimension they overflow.
Not require JavaScript or specific knowledge of each image's actual dimensions
I'm not sure if this is possible. I can make a (bad) approximation of what I want with the following markup:
<div class="thumb">
<img src="360x450.jpeg">
</div>
and CSS:
.thumb {
width: 200px;
height: 150px;
overflow: hidden;
}
.thumb img {
min-width: 200px;
min-height: 150px;
width: 200px;
}
This attempt breaks in a variety of ways:
Images that are in portrait orientation will be sized correctly, but will overflow through the bottom of the container, resulting in vertically-off-center cropping.
Images that are wide and short will be distorted in the horizontal dimension because of the hard-coded width and min-height rules.
But without that hard-coded width, images that are larger than the minimum height and width will not be resized at all.
If it's at all helpful, I've put up an example that will (hopefully) illustrate what I'm trying to do, here:
http://overloaded.org/tmp/imgtest/
http://overloaded.org/tmp/imgtest/imgtest.zip
I know that I can solve this problem by omitting the <img> element altogether and instead pulling the thumbnails in as a centered background image on the containing element, but, if it's possible, I'd like to keep the <img> elements in the page.
Thanks for any help or pointers you can provide!
Edit: I suppose I should note that an ideal solution will work in IE 6+ and modern browsers, but any solution that works in IE 9+ and other modern browsers (recent WebKit, Gecko, etc.) will be gladly accepted.
You can (kind of) achieve this with the CSS3 background-size additions: contain and cover.
Live Demo
contain (top picture) fits the entire image, keeping aspect ratio. Nothing is cropped.
cover (bottom picture) fills the containing element either vertically or horizontally (depending on the image) and crops the rest.
Possible, probably.
Also, probably not the best idea. Your big issue to overcome here is orientation of thumbnails. What if you're dealing with a panorama? Certainly, shrinking it down is going to create a very unsightly "squished" image, as would a very tall image. It's rare that everyone deals in 4X3 or 16X9 100% of the time. So, you'll need a mechanism to pad out the image. Even if the ratio is correct, it's not going to resize as cleanly as you could with a program like Photoshop or Gimp.
The other major issue in this thought process is that you're going to be sending massive amounts of unnecessary data to the server via the larger images. It'll take longer to load, fill up the DOM unnecessarily, and overall just inhibit the UI experience.
There are a number of ways to get around this, none of them pure CSS. I've tackled this several times, each in a unique way based on the client. For one client that wanted things totally custom, it was a custom uploader, resizing via iMagick (part of image magic) and custom CSS/Javascript for the album with major interactivity. In another instance, I use Gallery as the backend--handling the thumbnail creation, uploading, titling, cropping, and organizing-- and then just pulled the reformatted image links out of the DB to display them in a more appealing manner. You could save yourself even more trouble and just use something like the Flickr api to pull images for your use.
Here's a tut on using ImageMagick to do thumbnails.
.thumb img {
max-width: 200px;
max-height: 150px;
min-width: 200px;
min-height: 150px;
}
Well I know for thumbs you would want it max and min if you want a smaller image to make it bigger and bigger image to make it smaller.
try to set max-width and height and not min because if the image is not exactly that size it will overflow :)
I just finished reading YSlow recommendation to always define the image dimensions (height/width) to improve HTML rendering performance.
However, I don't know the image dimension I'm linking too.
What I do know is that the height will never be larger than 200px and the width will never be larger than 300px
Would I be a benefit if I defined (CSS) :
img {max-height: 200px; max-width: 300px}
For HTML performance rendering?
No, setting the max-width and max-height doesn't improve the performance.
The reason for specifying the width and height of images is that the browser will know exactly how much space the image will take up. If you leave the image size unspecified, the browser has to reflow the layout when the image loads.
You can see this nasty effect on some pages, where the page is first loaded with no placeholders for images, and then the contents jumps around making place for the images as they load.
If you can't specify the size of some images, don't worry too much about it. Just make sure that the layout behaves nicely when the images load, and don't jump around too much.
Setting the max height and width of an image in the css will make the img tag resize the img based on the contraints but if you are using a backend scripting language like asp.net or php you an use their img libraries to scale the image on the server side an either save then to the hard drive to use later or resize on the fly.
You can check out http://shiftingpixel.com/2008/03/03/smart-image-resizer/ for php as a starter
Or if you are using .NET you can check out this link http://weblogs.asp.net/gunnarpeipman/archive/2009/04/02/resizing-images-without-loss-of-quality.aspx
Images with different proportions would not look good, since they would be scaled. I would not recommend this.
In this case I would definitely not set the height and width of the image since you don't know what it is going to be. If you know what the size is going to be then setting is good because it will cut down on the amount of repainting and reflow that the browser has to do when rendering a page.
The less it has to do then the better the performance will be on the client side because you are not making the browser work too hard.
Stoyan Stefanov explained it really well in a recent blog post
I think You'd rather want to wrap that <img> into a <span> or <div> element with max-height and max-width set. Also, it ( span or div ) should have overflow:hidden set so the image doesn't go out of the div's range.
It definitelly isn't recommended to set these setting directly to image because You'll get different and slower rendering in different browsers.
I've learned that it is a best practice to explicitly specify image dimensions. The browser can then already layout the page while still downloading the images themselves, thereby improving (percieved) page rendering time.
Is this true? And if so, is there a difference in specifying the dimensions in either HTML or CSS?
HTML: <img src="" width="200" height="100">
Inline CSS: <img src="" style="width: 200px; height: 100px">
External CSS: #myImage { width: 200px; height: 200px; }
According to Google Page Speed, it does not really matter if you specify the dimensions via CSS or HTML, as long as your CSS targets the IMG tag itself and not a parent element :
When the browser lays out the page, it needs to be able to flow around replaceable elements such as images. It can begin to render a page even before images are downloaded, provided that it knows the dimensions to wrap non-replaceable elements around. If no dimensions are specified in the containing document, or if the dimensions specified don't match those of the actual images, the browser will require a reflow and repaint once the images are downloaded. To prevent reflows, specify the width and height of all images, either in the HTML tag, or in CSS.
However, note that they advise not to resize the image using these dimensions, ie to always use the real dimensions :
Don't use width and height specifications to scale images on the fly. If an image file is actually 60 x 60 pixels, don't set the dimensions to 30 x 30 in the HTML or CSS. If the image needs to be smaller, scale it in an image editor and set its dimensions to match (see Optimize images for details.)
I tend to do it in the CSS. This is certainly a win when there are multiple images with the same dimensions (so you can do stuff like .comment img.usergroup { width: 16px; height: 16px; }), and have the same images subject to scaling in different stylesheets like user-selectable themes.
When you have completely independent images that are used on the site only once, it doesn't really make sense to abstract their size out to CSS, so the HTML version would probably be more appropriate there.
I think CSS gives you more flexibility: you can specifically set the width or height while setting the other dimension to auto. But when setting both dimensions, I don't thing there's a difference.
This does not answer your question directly, but I would not rely on the dimensions of your image for page layout. Instead include the image in a block level element. This relieves both the HTML and CSS from having to hold information that it really shouldn't as the image may change from time to time.
If you put a large image in an HTML page without dimensions, you should definitely notice the page layout shifting as the image is downloaded (over an internet connection, if not locally).
As per other answers, it doesn’t make much difference whether you do this in the HTML or the CSS.
I'm working on a website with a em-based layout (so it can stretch and compress gracefully when users increase or decrease font size). This site has a header that should be displayed across all pages. I have a "header" div in all pages, and the site-wide css file includes the code:
#header
{
width: 50em;
height: 6em;
margin-bottom: .5em;
background: url("/IMAGES/header.png");
}
The problem is that this doesn't really stretch gracefully. When text size increase, the height and width change, but **the image doesn't increase in size; it simply repeats*.*
How can I make my image stretch and squish, instead of repeating or getting cut off? (I'd like a css-based solution if possible... I've got some html ideas in store, already).
There is no way to use css to strech a background image. You would have to use javascript or something similar. However, if you have an image that doesn't need to be repeated (e.g. blends into the background), you could do something like this:
background-position: center center;
background-repeat: no-repeat;
Addendum: The position has the following format: <top|center|bottom|xpos> <left|center|right|ypos>
where xpos and ypos can be given in the regular fashion (em, px, %, etc...).
The only way I've ever found is:
Set background of #header to bgcolor of header image.
Place new div inside #header
Split header image into 2
Set left half of new image as #header background aligned-left
Set right half of new image as #header.div background aligned-right
Of course that's only going to work with appropriate images though.
I'm pretty sure you can't change the scaling of background images. If your header.png file was included as an img tag, then you could set its height and width to be a number of ems and the browser would resize it (usually making it look like crap though).
Remember as well that pretty much all the modern browsers do page zooming these days, which will scale everything up without changing your layout too much. Perhaps tell your users to use that feature?
#Pianosaurus, I think your idea may be the simplest, although limited. Simply, don't stretch the image, but make sure it looks good when it's not stretched (center it, and don't let it repeat). Also, if you use a fair amount of padding at the edges of your header image, sizing the page down wouldn't cause such big problems, either.