Images On The Web
Using the web to display and send images presents its own special set of problems.
There is a maze of different computer graphics formats, display differences depending on each individual computer set-up, and file size issues to tiptoe around.
As examples, you may try to send your Aunt Hilda an image which her system doesn't know what to do with, because it is rendered in a graphics format which her computer doesn't know about.
Her computer may be a pre-Flood model, capable of displaying only 256 colours, so making your beautiful holiday seaside scenes look like something out of Picasso's blue period.
She may still be using an old modem, or be on a very slow dial-up connection, so qualifying for superannuation while she waits for your 6 megabyte photos to come down the line.
Ok, so the above three scenarios are at the extreme end, but they give an idea of the possible problems.
Luckily, this particular maze isn't really that difficult to navigate.
Unless you're sending images which need to be publication-quality, sticking to two main formats for rendering those images should avoid most potential traps.
These are the JPEG ( Joint Photographic Experts Group, pronounced "Jay-Peg" ) and GIF ( Graphic Interchange Format, pronounced with either a hard or soft "g" ) formats.
The main advantage of these two formats is that they use compression to reduce the file size of an image, and thus the time it takes to load or send, without compromising its quality too much.
This avoids potential problems with huge image files
being blocked by email system filters, or taking forever
to download by email or via a browser
( such as Internet Explorer ) viewing a web-page containing
that image.
For example, an averaged-sized simple photograph in the Windows bitmap ( .bmp ) format weighs 405 kilobytes, while that same photograph in the GIF (.gif ) format weighs 79 kilobytes, but only 18 kilobytes in the JPEG (.jpg or .jpeg ) format.
A simple cartoon image which weighs 120 kilobytes in the
bitmap format, is only 19.7
kilobytes as a JPEG, and 18.0 kilobytes as a GIF image.
Photographs, especially complex ones containing many shades, are best saved in the JPEG format, while small icons, and line drawings containing only a few colours or large patches of the same colour, are best saved in the GIF format.
The JPEG format has the added advantage of offering a sliding compression rate, trading off image quality with file size, while the GIF format is capable of transparency, and is less prone to subtle colour shifts.
Of course, you'll need an image editor to convert the images into different formats, which you'll usually do by using the editor's Save As command, and looking for a format option.
Even Microsoft's native paint programme will convert images from bitmap to the JPEG or GIF formats. For more sophisticated editors, Paint Shop Pro and Adobe's Photoshop are considered the top of the line, or you can choose from a range of cheaper and free editors at Tucows
Once the conversion is done, you can send the image by attaching it to an email, or if you want to publish it, post it to your web site using an FTP programme. It is then viewable, for example, by typing http://www.mycheaphost.co.nz/images/my_dog.gif into the address bar of your browser.
To send an image using Outlook Express, create an email as usual, and use the Attach button with the paper-clip icon.
And, if you're sending a number of images, consider further reducing download times by packing all of your files into one archive file using a programme such as Winzip or WinAce .
May 30, 2004
site by Urban Legend Designs