When developing a website I often use background images for banners. When this website is in a CMS, the images paths come from the database (user uploaded). So I ended up using a style="background-image:url(myImageFromDB.jpg)"
However, this becomes an issue when I want to replace this image with smaller versions of the same image.
A lot of tutorials/guides out there, assume that you already know the path to this image, so you can just use #media queries to easily replace them. But if the path is dynamic, then I can't use media queries (unless they are dynamically written in the head of the document).
So how are people dealing with this issue?
Not using background-images? (using instead?)
Dynamically writing media queries at the head of the document?
Using JS to dynamically load the correct images?
Resizing images dynamically on the server?
My downsides of each method:
1. Downside, can't use some good options such as background-size:cover
2. Need to write server side script figure out what image to load
3. Probably the best option, but need to wait for the JS to load first
4. I have tried this, but without much success.
one thing you can do..
You can assign its width using view port width like width:90vw;.
1 vw=1/100 of total view.
so you need not change the image for small screen.
you can just simply add this in your media query and default css also.
width:90vw;..
you can change width as your requirement.
so it will act dynamically.
not need to change the image.
hope it works.
Related
I regards to responsive design, if I have a set of large background images that fade between each other on large screen sizes and have them hidden on smaller screen sizes do they still load on the smaller screen sizes? I don't want to use unnecessary bandwidth if the images aren't going to show. It seems that they do not load on my computer, but it is difficult for me to test for every possible setup. If they do load and not show by default, is there any way to fix that? Also, I'd like this to work without having to use javascript, if possible.
"Adaptive Images" detects the user's screen size and automatically generate cache for that particular size.
I have used this previously in some of my projects, it works like a charm.
You can find more information here and here
And you can't avoid Javascript, that's the only solution as per my knowledge. But it is easy, all steps are given in above links.
Yes, most browsers will download images even if you have them hidden.
There is no way to stop image load with just html and css alone. JS is the best way to do this and it is also very easy, so you might not have any choice but to use javascript.
Just incase you decide to use javascript you should check out lazyload, it is very simple to use.
http://www.appelsiini.net/projects/lazyload
I have a web page which loads almost 70-80 images on the web page. I already have implemented lazy loading. Should I keep these images on local server or on some image site like picasa and reference it from there ? or is there any better option ? What would be the best way to load these many images without loosing performance and efficiency ?
Please suggest.
One more question - is it good idea to add css animation effect to those images ?
There are a number of things you can do.
Use a tool like smushit - www.smushit.com to optimise images and reduce loading times.
Make sure that you are not resizing large images by setting incorrect widths and heights.
Call images from a subdomain on your server.
Combine images used as backgrounds/display elements into a single image (known as a sprite), and use css to only call specific areas of the single image - this means it will only be loaded once, reducing HTTP requests.
You can get some advice on using Sprites here: http://css-tricks.com/css-sprites/
You can also get some more info on page loading times, and things you can do to optimise by using GTMetrix tools at http://gtmetrix.com/
I'm trying to create a gallery for a mobile site where I have different stylesheets for different sized devices. Within these stylesheets I have several classes which simply set a background url property to each image I want in the gallery.
Only one of these will be displayed at a time. And I will be cycling through the classes using Javascript to display them in a slideshow type presentation.
I am wondering is this method more bandwidth efficient than having all the images as individual img tags within the DOM? By setting these url properties do they get downloaded to the user's browser when they first load the site or are they only downloaded when the class gets set on a div in the DOM?
Simply I am trying to avoid having to download all the different images to the user's device at once. If you know any alternate methods which are better for this sort of thing I am also interested.
You are right, When you set the image backround, the image will only be downloaded if it is used, By this I mean, used as a style on some dom element.
Alternatively, you could 'change' the background-image css property using javascript. This way, you don't even have the image url in your CSS.
If bandwidth is your biggest concern, I would urge you to have a look at the inspector in webkit browsers like Chrome or safari, or with firebug on Firefox to see the 'network' tab, there you have a clear overview of what is loaded, how ( what order ) and how to optimize things. You can also make some stupid mistakes clear like downloading multiple times the same library from different locations and so.
If you just declare the class in css it shouldn't download anything before it is set. however it is a round question and the answer could take a lot of different shapes.
So I would say that yes it is a good way to do it, and it should be more bandwidth efficient (if you don't know that all the images will be loaded eventually anyhow, since you will typically have asynchronous image-loading either way it shouldn't matter much. I guess that if you only load one image initially the other images (i.e. the mentioned img tags) will not interfere making the load a bit more smooth?).
I find it to be a cleaner solution at least if you aren't sure which images will be viewed (which is likely to believe) to use your css-approach. also it's easier to maintain and provide a better design.
That you will be using javascript indicate that you are also doing the client side. And that give you control to choose what to do which is great :)
One alternative could be to have a local cache of the images as well, but that really depends on the problem at hand, if you will have different images and no real possibility to know in advance which images you will need (and perhaps not even how many of them?) then I think that the cleanest way is the way you purpose.
i.e. set up (or dynamically create) css-classes for images and handle all the logic in javascript.
I'm kind of sure this is not possible but I ask because it seems unbelievable.
I have some elements styled for reponsive design
img {max-width:100%;height:auto;}
but the images have to be different depending on the device (I won't load heavy wide screen images on a phone device).
Since media queries aren't supported inline, I could go for a css background solution, but background-size is not perfectly supported and honnestly it would look more like a hack.
Can anyone confirm that "widely supported device related responsive images" are not properly possible ?
Thanks
If I understand your question correctly, you are looking for a way to deliver a different image depending on the viewpoint.
Adaptive Images could be the solution you are looking for. Easy enough to setup and confirm.
A second possiblity which might give you even more control is Adapt.js . I've used it with good success on several sites. You load a small javascript file in the head of your document. This tests viewpoint width and then dependending on the results, it will send the appropriate CSS file. It has wider browser support than #media requests.
If you could live with using background images, then it would work well, and since you could specify different images for different viewpoints, you aren't up the creek with browsers that don't understand background image sizes.
Good luck!
You could try the Responsive Img jQuery plugin.
It's made to automatically create and swap in different-sized images at different breakpoints, based on the container's width.
If you already have different versions on your image created and on your server, the plugin will just swap those in at the right breakpoint sizes.
Therefore, you can create new images for all the different breakpoint sizes you want, and the plugin takes care of the rest.
It's not CSS, but it gets the job done.
2014 update
There is a nice and new technique here :
http://filamentgroup.com/lab/responsive_images_experimenting_with_context_aware_image_sizing/
It requires a small js, a 1x1px blank image, a few extra markup for img tags, and some .htaccess rules.
Seems to work fine so far.
I know of 3 main ways to shrink images:
Using the img tag WIDTH HEIGHT
Putting all the images in a DIV and then scaling the whole div.
User zooming with ctrl + mouse wheel.
I have some pages with huge amounts of images. What I have noticed is that there is massive speed difference between the methods. Method 1 kills firefox very quickly. Method 3 seems to be the fastest on all broswers I have tried.
Does anyone know of any other methods? And is there a way through javascript/css to specify what the browser zoom level should be so I can at least use the fastest way?
The easist on the client would be scaling the images on the server and sending them to the browser, however it would take some serious CPU power on the server end (unless you cache them, and serve them up afterwards). You can achieve this with PHP quite easily. Depending on your purposes, you could simply write a script that takes all the images in a directory, resizes them and saves them to "thumbs/".
If you don't want to use anything on the server, I would either go with option 1 or question why there are so many images on one page to bein with. Try adding some pagination or something. If the browser slows down while using such a basic method of resizing images, there might be some refactoring in order.
If you're going to be resizing images why not have the images themselves be smaller. That will load the fastest out of any method you try. You can use PHP to create thumbnail sized images, and a link to the full sized image if they need to see it. Remember, even if you resize an image with the height/width the browser still loads the full image.
See http://articles.sitepoint.com/article/image-resizing-php for a tutorial on image resizing in php.