putting out there for others to enjoy!
But many folks don't seem to have much of a handle on digital image creation/ manipulation/ for the web. Been talkin about some aspects of that on other forums, and lookin at martinsr's latest "handout" on the basics, got me thinkin maybe I'd put a few "helpful hints" up for folks to ruminate over, and see more & better pics around here as a result.
Although I'm not an ace photographer, or a computer guru, I've gotten fairly good at dealing w/ web images, so . . . .
A small FAQ for image tools [or for the pictorially challanged]:
There's a gazillion digital image formats, many of which are 'proprietary' and not generally useful. The basic file types for the web [and Email] are .jpg and .gif. there are others, but they're not often used and not all image editors handle them. And .bmp's - Microsofts proprietary format - are useless for anything other than Windows desktop images.
In a medium size,
for the same image, the jpg makes a smaller file size than the gif, unless the gif is really bottom end in terms of color and DotsPerInch. That's because the jpg format is a "compression" format, specifically designed to minimize file size. Normally you'll only be concerned with the jpg [or jpeg - Joint Photographic Experts Group]. The gif format is best used for icon-like images [which are usually 8, 16 or 256 color], in the smallest sizes. The gif is most useful for the smaller images on a web page - like all the little icons along the left side of the forum pages, the avatars used on forums, and the smilies. Of course when there's tooo many of those, page loading can be slowed even tho' individually they're small.
Due to the limitations of dial-up internet connections, and the cost of "bandwidth", it is very desireable to stick to the smallest physical and file size consistent with decent visual impact. What that means is that for a pic that will only be used on the net, 72dpi is fine, 100dpi is generous, 150dpi is excessive, and 300dpi is obnoxious. In the same vein, over 50% of web surfers still use a screen resolution of 800x600 or smaller, so images that are larger than 750x500 [wide x hi] will result in lots of people having the irritation of side scrolling to see the pic, and even up/ down scrolling will ruin the visual impact of a good pic.
So -> if your screen resolution is 800x600, and your browser scroll bars, button bar and address bar knock a couple inches off all around, an image that is 1280x1024 will be about twice as wide and twice as high as you can see at any one time.
To see some comparisons, right click pics on the net and look at "image properties" - note that the gif images will usually be 4-5-6 bits per pixel, and fairly small file sizes, while the jpgs are 16 or 24 bits and much larger file sizes - but still under 100k. If you find an image that is slow loading and larger than your screen, compare that to see what "doesn't work".
The default settings on most digital cameras and scanners tends to be 300dpi and 1024x768 or even higher. Not good -- for bandwidth or screen size! It's a very small percentage of surfers that have larger than 17" monitors, and the higher the dpi, the bigger the pic will be. If you have a digital camera and are taking pics for use only on the computer, you can usually do fine at the "low quality" setting, and if you use the medium setting for the sake of "archive material" photos, you'll need to resize the images and/ or optimize them for the web. The highest quality setting is only useful if you intend to make hi quality paper prints of those images, or if you want to "zoom" on details in the photo editor. If you want a high quality copy of the pic, but use the same pic on the web, save a 2nd, web optimized version.
There are a number of ways to reduce file size, the first being to reduce the physical size. look at pics closely and see if you can crop most of the non-informative surroundings away and get a bit closer to the "meat" of the subject. Do we need to see every house in your neighbor hood, the foreground down to your shoelaces, and the sky up to Venus in order to appreciate your truck?!?
After cropping, reduce the physical size to less than 550 pixels wide and less than 400 high. that will allow the pic to be as big as possible on the maximum number of screens without causing side scrolling, or causing dial-up connections to choke. If that doesn't get the file size below about 75k, try
reducing the colors used from what will probably be "16 million" or 64k [24 bit] to 32k or lower [16 bit] - if your app supports that function. beyond that, you need to "optimize" it.
If you don't have an image editor consider the following [scanners and cameras will include "crippled" free versions of one commercial app or another, most of which can be used for the basic functions]:
My personal choice is Paint Shop Pro, up to version 6 - higher versions are clutter for most of us. Adobe Photoshop is prolly the most common app - for a variety of reasons that don't make it work better than PSP.
IrfanView is a free, simple and excellent photo viewing and manipulation app, that will "run" your scanner, allow you to put text on pics, and crop them down to size, among other things. Pick up the 'plugins' too - the whole rig installs in seconds without messing up your system.
The other type of app that is useful if you plan to do a lot of "web work", is an
Image Optimizer, like Ulead SmartSaver Pro. This app can change a jpg from the "normal" 100% to 75% or 50%, which is usually fine for the web, and will bring say, a 100k file size, down to as low as 30k. Works on gif's too.
For a bunch of free and not so free editors,
see the list at download.com For an online free editor that can be used if you've just got the occassional pic to deal with, try
http://www.myimager.com/ - there are other sites out there similar.
The bottom line:
Obtain an image editor, and take some time to learn it - the more you plan on doing, the better the editor you should have. Resize your web pics to about 600x400 max, with a file size of under 60k [30 - 50k best]. if you're going to put an image "inline" on a forum thread, rather than just link to it, the size should be less than 600x400 [usually 400 pixels wide at most], so as to avoid forcing the page wider than most viewers screens and causing side-scrolling.
end of lesson - if anyone is interested in more info about this or other "image on the web" topics, I can carry on another time - if anyone wants to improve on this, take it away - if interested powers-that-be want to 'archive' this someplace, fly at it . . . . .
my thoughts never copyright or copyleft
nor
my website .
Bill
