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JPG Compression - The Bandwidth Saver
Mr.Tweak writes "TweakTown has posted an article entitled "JPG Compression - The Bandwidth Saver". An article for webmasters and site owners showing how they can significantly reduce the amount of bandwidth they use by compressing JPG images, one of the most common formats for web images. If you own a website and don't yet have knowledge in the field of JPG compression, you should find this very interesting indeed - Save money on bandwidth and please viewers at the same time with quicker loading webpages. They also talk briefly at JPEG2000."
In other news:
Anonymouse Cowarde has posted an article entitled "Power Switch - The Energy Saver". An article for geeks and computer owners showing how they can significantly reduce the amount of power they use by turning off your computer when you're not using it, using one of the most common buttons found on the front of most PCs. If you own a computer and don't yet have knowledge in the field of energy, you should find this very interesting indeed - Save money on electricty and please your significant other at the same time with a quieter room and lower energy bill. They also talk briefly at APM.
Short run down of the linked-to article:
Non-compressed images have a large filesize and cost a lot of bandwidth, compressed images look almost as good and cost less bandwidth.
Guide to compress images in PSP 7: save, move slider.
conclusion: compressing is good, hope you found this useful.
*shakes his head sadly* Slow down are fine, but c'mon - we're geeks you know; we can be expected to at least know *some* things...
Pardon me, I seem to have accidentally stepped into a conversation from 10 YEARS AGO.
Now, I can understand if slashdot wants to put techie reviews or such other geek stuff. That's understandable, in the case of YRO, company product release (that april spoof about sponsoring products was true, wasnt it?), and software issues.
HOWEVER, this is a geek site, which we talk as deeply as going about SMP on x86 systems and remodding systems into other cases (mechanics and engineering, lest that be software or hardware). However, that journalistic line (if there even was that line) has been crossed with this idiotic article. Let's re-read this again to see if it doesnt state the obvious. Also, I'm going to _assume_ that techie people on this website (most all) knows that jpeg is a compression....
Compression - The Bandwidth Saver
Hell, even non-techie people still know that if I zip that file, it doesnt take as long.... This article just insults our intelligence. Slashdot is becoming more and more like TechTV for the net.
And as a last mote, moderators, pay attention to *important stuff* below every post. This article is anything but offtopic.
While compressing your images should be right up there on the Web designer 101 course, sometimes I despair that the wrong types of compression are chosen.
JPEG is an excellent compression method for photographic images, both colour and greyscales. The image distortion is not noticeable by most people even at high compression ratios and the resulting image is close enough to the original.
JPEG is NOT an excellent compression method for line diagrams, maps and bitmaps featuring a limited colour palette - the artifacts created by the transforms used by the algorithms blur rapid changes in colour and can make text unreadable. Even worse, for most diagrams, PNG lossless compression yields smaller results because of the limited palette and large amount of redundancy inherent in the data.
JPEG 2000 promises even better compression ratios with superior image quality. Wavelet compression methods tend to reduce the amount of blur caused by the discrete cosine transforms and are better at handling rapid changes in colours. But that doesn't mean that it is a blanket solution.
I also look forward to the day when SVG is a widely available and widely supported browser option. We can all benefit when complex layouts can be described in terms of vectors and colour fills rather than overlarge and complex bitmaps for the classic web page touches like 3D colour balls and arrows. That will also save bandwidth while increasing the flexibility and variety of images on the web.
Cheers,
Toby Haynes
Anything I post is strictly my own thoughts and doesn't necessarily have anything to do with the opinions of IBM.
Although jpg compression is definitely helpful, the article forgets to mention that two image formats are supported by all browsers. GIF being the second.
In addition, 4.0 and newer browsers support Portable Network Graphics (PNG).
GIFs should be used for vector based graphics
No they shouldn't. Use PNG for still images. Use SWF (now an open format) or MNG (not much browser support yet but works in Mozilla and Konqueror) for animations.
and provides a better overall quality/size advantage when done right.
PNG can be 10% smaller than GIF when crushed properly.
Will I retire or break 10K?
At my last job, we wondered why our carefully tuned images looked like shit on AOL. We found they were recompressing our jpegs to make them much smaller (and thus lower quality). So we now send AOL really high quality jpegs so that our images don't get trashed as badly by AOL.
Plato seems wrong to me today
You laugh, but I do have a couple pictures I've gotten of people over the years ... that are small (res wise) .JPGs, about 400-600kb each.
Reminds me of the friend who wanted to know why his page of family photo thumbnails was taking so long to load. He was using JPEG files, and was shrinking them down to 128x128, but the page was still taking many minutes to load. I took a look at his HTML, and saw that each thumbnail was specified as <img src="p000001.jpg" width="128" height="96">, etc. The trouble was that p0000001.jpg was the full-resolution image! Each one weighed about 500K. He had "shrunk" them by changing the width and height in the img tag - in other words, the browsers were downloading twelve or so full-size images then scaling them into thumbnails. The good part was that clicking on a thumbnail, to see the full image, was instantaneous as the full image was already in the browser's cache.
I didn't have the heart to tell him how clueless his page was.
--Jim
I'd like to see some kind of lossy PNG
That's JNG (JPEG Network Graphics) which is JPEG wrapped in PNG-style chunks along with an optional alpha (transparency) channel. Mozilla will display them and IrfanView will process them.
The JNG spec is available somewhere on the PNG web site, http://www.libpng.org/pub/png