It is important to remember that a 64
grey-scale image takes up just as much room as a 64 color image. If you are
working in grey-scale, limit the number of greys as you would limit the number
of colors!
GIF is by far the most popular and supported graphic format. It allows for high resolution with relatively low file size. Almost every graphics viewer is capable of displaying GIFs. If you can, make all your graphics GIFs.
JPEG is another very popular format. Netscape and Mosaic can view JPEGs as well. What's the difference? JPEGs take up less file space than GIFs. But because they are compressed more, they take longer to display. This is a tradeoff you will have to decide about. Of course, there is no problem with using both file formats.
There are a few things that determine the size of a graphics file. One is the format that the file is in. For example, a TIFF or a BMP is usually larger than a GIF version of the same graphic. And the JPEG version is even smaller than the GIF.
Second is the actual size of the graphic itself. A small, thumb-nail graphic is going to load a great deal quicker than a version of the same picture that fills the entire screen.
Third is the number of colors in the graphic. It is important to remember that the more colors you have, the larger your file becomes. A 16 color graphic often looks as good or better than a 256 color or even a 16 million color version, but takes up much less room in a file, and thus loads much faster.
It is important to remember that a 64
grey-scale image takes up just as much room as a 64 color image. If you are
working in grey-scale, limit the number of greys as you would limit the number
of colors!
You may wish to consider editing the image in a graphics editor. L-View for Windows offers some very extensive editing capabilities (such as text insertion). Photostyler is an excellent tool for exiting graphics and is a full-blown paint and edit program with many professional-quality features. Some basic editing you may want to do is simple drawing or adding the title of the graphic as TEXT in the graphic itself.
For an added touch, you may want to change the background color of your image to match the viewer's background. If you use XV's color substitution, set the background to Mosaic Grey:
In Windows: 192-192-192
In Unix: 191-191-191
has a transparent
background; and so it blends into the page.Interlaced GIFs appear first with poor resolution and then improve in resolution until the entire image has arrived, as opposed to arriving linearly from the top row to the bottom row. This is great to get a quick idea of what the entire image will look like while waiting for the rest. This doesn't do much for you if your web browser doesn't support progressive display as the image is downloaded, but non-progressive-display web browsers will still display interlaced GIFs once they have arrived in their entirety. (taken from Sunsite) Information on both can be found at JPL or this Sunsite Page
