This chapter is from the book
Where Fireworks really shines is in enabling you to export graphics into many
different formats quickly and easily, with fine control over every detail,
including colors, transparency, and compression. In the previous hour,
"Image Collection and Management," it was pointed out that the
Fireworks Save command saves your work as a Fireworks PNG source graphic. To
create other kinds of graphics in many different formats, using the Export
command will be discussed here.
In this hour you will
Learn about the different export formats
Preview and compare different export options
Change settings to optimize quality or file size
Save custom settings to make output more consistent
Create a simple placeholder Web page graphic
Working with Different Output Formats
There are a number of different graphics formats that Fireworks can export,
each with its own strengths and weaknesses. For instance, exporting as TIFF
might create a file even bigger than the Fireworks source PNG. JPEG is
particularly bad as a format for images with lots of text, like a screenshot or
button. The following is a list of different file formats that can be optimized
and exported with Fireworks:
GIF—GIF images are one of the most widely supported formats for
computers and the Web. Images with lots of text or line art and a limited
palette work best as GIF images. GIF images have a palette of no more than 8
bits but can create very small files. GIF images can also contain a transparency
mask.
Animated GIF—Animated GIF export creates files of the same
format as regular GIF files, but they can contain multiple frames and display
them at intervals to create moving images. Animated GIFs can become very large
unless special steps are taken to optimize them.
JPEG—Another widely used format for the Web is JPEG, which is
best for photos and other images with a full range of colors. With JPEG you can
vary the level of compression by trading image detail for file size—the
smaller the file size in bytes, the less detail the image will contain.
PNG—PNG export is for creating PNG graphics without
Fireworks' special features. Most Web browsers and graphic applications do
not support all of Fireworks' special PNG features but do support the more
basic format features. The basic PNG format uses non-lossy compression like GIF
but saves more detailed color and transparency information.
WBMP—The wireless bitmap format is used for creating graphics
for tiny, monochrome displays common on wireless devices, such as cell phones
and PDAs. These images are naturally very small because each pixel must be
either black or white and the dimensions must be similarly restrained. Non-lossy
compression, such as GIF compression, is employed to make the files even
smaller.
TIFF—This format is often used in the print industry and for
moving images between graphics applications. Many Web browsers do not support
this format. TIFF files exported from Fireworks employ non-lossy compression and
can contain the full RGB palette plus an 8-bit alpha channel.
NOTE
When your image-processing software, in order to reduce the file size,
removes information that is more or less redundant to the human eye, this is
known as lossy compression. The advantage of lossy compression is that it
gives a very high degree of compression, often 5 to 30 times. The disadvantage
is that the quality of the image is reduced as the compression increases.
When you use a non-lossy compression format, all original information
will be saved in the image. The disadvantage is that the compression ratio is
much lower, leading to larger file sizes.
PICT—Used almost exclusively on the Apple Macintosh platform,
this format does not use compression; files can be made smaller only by
restricting the palette or dimensions. PICT image files are rarely used in Web
pages. They are used mostly in production as a backup or transfer format.
BMP—This is the basic image format for Microsoft Windows. Like
PICT, it can use the full RGB palette but does not use compression—but this
can also create very large files. For this reason this format is also less
common on the Web.