Images for the Web
The two most used image formats on the Web are GIF and JPEG.
There is also the PNG format. These format sometimes have sub-formats
(GIF87, GIF89a, Progressive JPEG and so on).
GIF is a bitmap image format on 256 colors with sequence-compressed
representation, which generates small size of image files for illustrations and
icons, which usually has homogeneous coloring.
It supports interlaced image, transparence and animation (multi-image).
JPEG - Joint Photographic Experts Group is a 24-bit (true-color, 16M colors)
image format, represented using compression with loss. This usually produces
reduced files for photos and complex images.
The compression rate can be configured:
the greater the compression, the smaller the resulting file, but also greater
is the quality loss related to the original image.
Another format, PNG - Portable Network Graphics, is a great promise, specially
now that Netscape and Microsoft Internet Explorer browsers support
this image format.
PNG files usually are smaller than the corresponding GIF and have better
quality than JPEG, besides PNG is a widely more flexible format.
And there's also a very importat point: the compression algorithms used in
the PNG format are public domain, in opposition to the GIF format, which
compression method is patented.
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Adding Images to Your Site
By Philip Greenspun, part of
Philip and Alex's Guide
to Web Publishing, Chapter 6.
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JPEG image compression FAQ - FAQs.org
Basic questions: What is JPEG, Why and when use JPEG,
JPEG compression and quality, JPEG software.
More advanced questions: Color quantization, Converting GIF images to JPEG,
loss, Progressive JPEG, transparency, file formats, compatibility,
various technical questions, Programs and hints for specific systems,
Freely available source code for JPEG.
When should I use JPEG, and when should I stick with GIF?.
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Optimizing Web Graphics - The Great Bandwidth Shortage
By ,
WebReference.com.
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Preparing Graphics for The Web
By Douglas E. Gray, 1996-7. JPEG File Format, GIF File Format,
Which Format to Use, Display Types, Tips and Tricks.
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Palette for WWW images
By A.J.Flavell & Glasgow University
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The Browser Safe Palette (BSP)
Victor S. Engel's No dither 256 color palette for Netscape.
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JPEG & GIF Crunchers
Free JPEG & GIF Optimizers by Spinwave.com
(Digital Frontiers).
Spinwave GIF Cruncher at WebReference.com.
- GIF Wizard
(link USWest)
OptiView Web Acceleration. "Accelerate your website!".
By Raspberry Hill Publishing Inc..
- Ulead WebUtilities.com
GIF Animator, SmartSaver, WebRazor, other utilities. Tutorials, Links, Books.
- Pixelsight Home
- DNA 3D GIF Animation
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Adobe Studio - Web design and graphics
Adobe Studio (free registration), Photoshop Expert Center.
GIFs & LZW Patent
Animated GIFs
Recomendações da Revista Internet World Brasil:
Imagemaps - Clickable Area Maps in Images
Image Libraries & Galeries
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