I'm trying to make a sick slider like this http://learnlakenona.com/
But I'm having major performance problems in chrome (it seems their site doesn't even run the slider on chrome). I'm displaying the images by using background-image CSS on divs, adding them as img tags caused even more lag.
I disabled all javascript and noticed I was still getting lag just with having some huge images sitting on top of eachother.
Here's just some images sitting there. Try changing the size of the panels, redrawing the images locks it up. (sometimes it runs okay for a bit, it's weird)
http://jsfiddle.net/LRynj/2/
Does anyone have an idea how I can get acceptable performance on a slider like this!? (images need to be pretty big)
Optimize your image assets by resizing them in an image editor or lowering the quality.
You can also use free tools online:
http://sixrevisions.com/tools/8-excellent-tools-for-optimizing-your-images/
The site uses HUGE transparent PNGs for a parallax effect, so:
you'll have to reduce the total weight of your images: you can try to convert these PNGs to PNG-8 if they aren't already. Quantizations algorithms and such do a very good job at reducing images to 256 colors without too much degradation of quality.
you've to keep transparency for the parallax effect. Both types of transparency are compatible with PNG-8: GIF-like opaque/tranparent bit of transparency on each pixel and "PNG-32"-like (PNG-24 + 8 bits of transparency) where each pixel has 256 levels of transparency. Adobe Fireworks is particularly good at creating such "PNG-8+alpha" images; converters also exist but they're not perfect (depends of your images).
loading the minimum part of your image that is seen immediately and only later the rest of your 9600px-wide (!) would greatly reduce the time to first view. You can achieve that by slicing your images by chunks of 1920 or 2560px, load the viewed part of the 3 images as background images and via a script that would execute only after the DOM is ready load all the other parts. Not too much parts because that would imply more assets to download but still not a 4MB sprite :) Bonus: by slicing your 3 images to PNG-8, each PNG will have its own 256-colors palette and overall quality will be better (not as perfect as a PNG-24 but better than a single 9600px PNG-8 that could only use 256 colors total. More shades of grey for the man suit in one PNG, more shiny colors for the ball-and-stick molecule, etc
EDIT: and don't ever try to load that on a smartphone! I do like Media Queries and avoid UA detection because it isn't needed most of the time and never perfect but that's one of the cases (choosing to load 8MB of images) where it'll be welcome... Ignoring users that don't have optic fiber and won't wait for your site to display is another issue not related to your question.
Related
I'm working on JS / HTML game, where all objects are HTML elements (mostly <img>). Their top and left CSS attributes (sometimes along with others, like margins, transformations etc) are dynamically modified by JS code (every frame, basically). I noticed a huge performance improvement, when I switched from using .png files to .gif (22 fps -> 35 fps), but still:
Can further reduction of files' size (by 10-30%) actually noticeably improve CSS transformation performance? I would just test it, but I'm talking about ~250 gif files; and I don't want to loose too much quality, too.
Reduction of the the amount of data(=file size) which will have to be processed, will normally have a positive performance impact, but how much impact it will have has always to be tested and measured, as it depends always on how well your code works together with all surrounding frameworks, the browser and even how the underlying hardware does calculations.
In a worst case where you have to create a lot of resizing an recalulate new pixels, especially if you have to increase the display size of your image again, you might even create a loss in performance.
There is no absolute answer to how good or bad your change will be, until you have tested and measured it in your system yourself.
About Reducing GIF File Size:
A positive factor here is when you cut the width and height of the image by half, the actual file size can be reduced by around 75%.
When using GIF images, reducing the number of different colors used in the GIF image will reduce the size as well. Often you can select the number of colors when exporting gifs from image editor tools. In Photoshop you have an option "Export for Web" which will try to set the optimal settings for usage in web pages.
Regarding Game Performance and Images:
If you already know how you will resize the images(fixed sizes like +50% and +100%), using CSS Image Sprites with pre-resized images can create a good improvement, as you won't have to resize the image, but just use an existing part of the sprite sheet. This will reduce the amount of processing for image manipulation, and therefore increase the performance.
If you want all at once, performance, quality and small file size, the best way to go is replacing as much raster graphics with vector graphics as possible. Most of modern 2D Games use a lot of vector graphics.
Vector graphics are easier to resize, as only the splines have to be recalculated and filled, resizing raster graphics causes calculation for each new pixel.
All common modern browsers support the svg format and can be sized through css. If you want try it out, a free open source tool to create vector graphics is InkScape.
Hope this helps.
Why don't you use JPEG? It's compact. Yes, Image sizes affect performance.
Also, check "CSS Image Sprites", You can have a single image with all your possible icons/images and can handle view using CSS. You'll get better performance as you'll be loading a single image.
I have a website which contains some images in index.php
The problem I am facing is the whole page is not loading at once, I think images are taking some time to load
So what I have done is, I am showing an loading image at first and then after some time I am showing the page, that resolves the problem. But I am curious to know is there any other better way to do this?
I prefer to optimise the hell out of my images.
PNG images
You can use pngcrush to optimise your PNG files for you, but personally I find that once I'm done with it pngcrush only succeeds in making it bigger.
Use Indexed-PNG wherever possible. This will limit you to 256 colours, and most graphics editors won't allow partial transparency in Indexed-PNG (but it is possible - you just need the right editor. I use a custom PHP script with the GD image library) but you can expect to drop file size down to just a tiny fraction of what it was.
Reduce the amount of colours overall. PNG compression works best with blocks of the same colour, so reducing the number of colours improves compression.
GIF images
Especially for animations, there's a lot of things you can do.
Reduce the number of frames. Avoid duplicate frames at all costs, and just set the previous frame to have a longer display time.
Use combine rather than replace if possible. You will again have problems with transparent areas, but by using combine you can have each subsequent frame only change the stuff that... changes. This avoids the redundancy of re-writing the entire image if only a small part changes. GIMP has a useful filter "Animation > Optimize for GIF" which will do this for you.
Reduce colours as much as possible. GIF is limited to 256 colours, but if you can limit yourself to 32 or so, you'll get a much smaller file.
Using the above techniques, I once managed to shove 8MB of raw image data into a 125kb animated GIF.
JPG images
JPG is great for photos, but cameras have a tendency to write MASSIVE files.
Play around with the compression factor. Start at around 40%, and slowly bring it up until it looks acceptable. GIMP will show you a preview and the resulting filesize, so make use of that to find an acceptable compromise.
Scale the image down. You don't need 9 megapixels or however massive resolution cameras take now...
The above should help you reduce the amount of size taken by your images. Obviously, you should also cache images appropriately, so they only need to be retrieved once. Also make sure that you specify width and height on image elements so that the browser can reserve the space for them and avoid jumping around as they load...
And you should be pretty good.
It's hard to say what other options are available without knowing what the page looks like, but one option is to reserve space for the images so that the page text renders quickly in the correct position, and the images then load later.
What are some tips of loading big image faster. I look at this website:
http://vivianoheatingandcooling.com/wp-admin
and this
http://iplanwebsites.com/404
Both of these are fairly large images but they load extremely fast. I've also seen website that will advertise something and have 2 big images on both sides of their content:
http://www.gamefaqs.com/
GameFAQs does this alot. What are they doing to load these big image so fast on top of their page content etc? Is there some trick I'm missing other than saving for web optimization?
Image optimization is one key, the other key is designing so the optimization is effective. That's not so easy with a photo, but you can process a photo to optimize a little better.
In the case of the jumping sheep, the image is actually pretty small, resolution wise. It's 550 x 1900 and weighs in at only 150k. Considering that's pretty much everything that's being loaded, there are very few requests to the server, hardly any overhead... That will load really fast on most decent internet connections.
The other image is an image with very few colors in GIF format. You can have really high resolution images in PNG and GIF and get very small files if your palette is relatively limited. This is where these formats shine - In this case, the image should have been in png. As a png, processed by pngcrush, it's only 40.5kb rather than 62kb.
So yeah, image optimization and reducing overhead (Only load what the user needs in each view) are big steps toward snappy loading of large images.
Let's take iplanwebsites.com/404 as example :
it's a big image by size (width X height = 550px X 1900px)
BUT it's a low quality image - 141,14 kb - That's why that image loads very fast
You can use a software tool to optimize your images, but you'll see some differences in image quality.
Same for, other two examples - they use big images but they only have some black simple shapes, and that means a small file size.
Remember : it's not about just the width and height, it's also about picture quality, number of pixels, number of colors etc.
Stefan
I was wondering if there is any other ways to compress my images or any script that would load the page faster / or the the images behind the scenes?
The site is very interactive and using very high quality layers of images for the main layout. I have already saved for web devices in Photoshop and re-compressed using ImageOptim, some are jpeg but the majority are png24 to maintain transparancy, they are all set in CSS.
I have used jpegs and css sprites where i can but there is one in particular of a tree illustration streching the full site length, that is really slowing up the loading time, is there any I could compress these images further or code them differently that I missed?
Any help would be great thanks!
You said you are spriting. That is good.
You can also use tools such as PNGcrush which attempt to make files smaller by dropping things such as meta data.
You should also send far distant expiry headers and use a cache breaker on your images, to ensure the images won't be downloaded again if unnecessary.
In Photoshop, choose file-> save for web, you will be able to find the best compromise between size and quality.
Do you really need the transparency there? PNG transparency is unsupported on some browsers and makes the page processing intensive and slow even on high end computers, depending on image size and quantity of layers. If you can show something of your site maybe someone can give more hints about how to optimize it.
You can compress them on the fly with Apache if that's your web server. One of many available articles on the subject: http://www.samaxes.com/2009/01/more-on-compressing-and-caching-your-site-with-htaccess/
I'm working on a web application where we have a very large image (4000 * 2000 pixels) that can be dragged about the place, zoomed in/out.
When the image isn't zoomed in or out, it can be dragged about very fast and it looks great. As soon as i change the size of the image by some factor, the dragging becomes dreadfully slow.
I have just noticed that I have a height attribute on the image, but don't have a width attribute.
This behaviour is similar in both IE and Firefox, for obvious reasons, it works slightly faster in FireFox.
I have been looking at the GoogleMaps where they also have a very smooth draggable images.
What sort of optimisation I can do to achieve a similar result?
Thank you
Google Maps relies on lots of small, tiled images, as opposed to one large image. That way, they can be loaded in and out of memory, as you move around.
The simplest way to optimise the image would be to slice it up.
If you want to offer multiple levels of zoom, you may also want to consider rendering images at different levels as well, rather than relying on the browser to image process at run time.
Additionally, look at the image format you use! GIF and PNG offer compressed file-sizes over images such as JPEG and TIFF (although, obviously quality does take a hit).