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.Remember that graphics increase the time it takesa web page to move across the network; large graphics mean substantial down-load times, which can try the patience of the reader, particularly one dialing in ona standard modem connection.Here is the single most important guideline a web designer can follow: Keep thefile size of your graphics as small as possible! The nature of publishing over anetwork creates a new responsibility for designers to be sensitive to the issue ofdownload times.Detailed strategies for minimizing graphic file size for each file format appear inChapters 14 through 16 in Part III of this book.Getting correct file sizes on a MacintoshIt is important for web designers to pay attention to file size, measured in bytes orkilobytes (K).On Windows computers, the indication of file size that appears inthe directory listing is an accurate measure of the file s actual size.The number theMacintosh Finder shows, however, is almost always inaccurate.This is because ofhow the Finder displays file sizes and how Macs encode files.Partition sizes.For one thing, the file size listings in the Finder are measured ineven partition units or blocks, and the larger your hard drive the larger theblock.For instance, on a four-gigabyte hard drive, the smallest block size is 65K,so even if a file contains only 1K of information, it will display as 65K in theFinder.You can use the Finder s Get Info command to get an accurate reading of howmany bytes are actually in the file.To open the Get Info box, highlight the filename in the Finder, then select File Get Info, or use the Command-I keyboardshortcut.The actual number of bytes appears in parentheses next to Size.This is not the case for all Macintoshes, however.Macs with the newer HFS Plushard-disk formatting allow variable block sizes, which allow the Finder to indicate38 Chapter 3 Web Design Principles for Print DesignersWeb Design in a Nutshell, eMatter EditionCopyright � 2000 O Reilly & Associates, Inc.All rights reserved.Graphics on the Webfile sizes more accurately.Macs shipping with MacOS 8.1 or later may have HFSPlus-formatted drives.The resource fork.Macintosh files may contain extra Mac-specific code called theresource fork, which is used for storing icons, previews, and file type information.Only the actual data (the data fork) in the file is readable by other platforms, sothe resource fork should be stripped out when the file is uploaded to a server.Thesize of the data fork is the only number you should consider, as it is the actualnumber of bytes that will be downloaded by a browser.Photoshop files.Photoshop usually saves files with an icon and thumbnail views ofthe image stored in the resource fork.You can turn these off (saving just the datafork) by unchecking the Icon and Thumbnail checkboxes under Image Previewsin the Preferences File Saving dialog box.When you use the GIF89a Exportfilter to create GIFs, only the data fork is saved, and its file size will be accurate inthe Get Info window.Using Snitch.Unfortunately, there is no way, using the Mac Get Info box alone, totell how much of the file size is the resource fork and how much is the data fork.Snitch 2.5 is a shareware utility that works like a beefed-up Get Info window.When you select Dates & Sizes in the pop-up menu, Snitch shows you the actualbyte sizes of the data and resource forks, as shown in Figure 3-3.Figure 3-3: Snitch shows the data fork length and resource fork length ofMacintosh filesSnitch, written by Mitch Jones, is available for download at http://www.niftyneato.com (there is a $20 registration fee if you choose to continue using it).In additionto Dates & Sizes it contains many useful tools for viewing and editing file typeinformation.Graphics on the Web 39Web Design in a Nutshell, eMatter EditionCopyright � 2000 O Reilly & Associates, Inc.All rights reserved.Graphics on the WebWeb Graphics Production TipsThe following is a collection of tips for maintaining quality in web graphics [ Pobierz całość w formacie PDF ]

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