Even in commercial software allowing special characters in file names is a BAD idea.. (which is why Microsoft and Adobe/Macromedia do not recommend using special characters in filenames either)
This is not about pleasing any IT purists, it's about BEST practices. Which is likely why the Zen Cart FAQ makes the same recommendation with regards to special characters, and does not "fix" the Zen Cart code to accept special characters in image filenames (which should not be included in filenames in the first place..)
It's been explained why these characters could not and should not be used. You do not agree with this, and that's fine.. We will have to agree to disagree.. If someone comes along to "fix" this, then great, but the upcoming IH2 release will not include code which allows special symbols to be used in image file names because the core Zen Cart code does not recommend this, and its not a recommended idea to use special characters in filenames.
http://msdn.microsoft.com/en-us/library/aa365247%28VS.85%29.aspx#naming_conventions
Naming Conventions
The following fundamental rules enable applications to create and process valid names for files and directories, regardless of the file system:
- Use a period to separate the base file name from the extension in the name of a directory or file.
- Use a backslash () to separate the components of a path. The backslash divides the file name from the path to it, and one directory name from another directory name in a path. You cannot use a backslash in the name for the actual file or directory because it is a reserved character that separates the names into components.
- Use a backslash as required as part of volume names, for example, the "C:" in "C:\path\file" or the "\server\share" in "\server\share\path\file" for Universal Naming Convention (UNC) names. For more information about UNC names, see the Maximum Path Length Limitation section.
- Do not assume case sensitivity. For example, consider the names OSCAR, Oscar, and oscar to be the same, even though some file systems (such as a POSIX-compliant file system) may consider them as different. Note that NTFS supports POSIX semantics for case sensitivity but this is not the default behavior. For more information, see **CreateFile**.
- Volume designators (drive letters) are similarly case-insensitive. For example, "D:" and "d:" refer to the same volume.
- Use any character in the current code page for a name, including Unicode characters and characters in the extended character set (128–255), except for the following:
- The following reserved characters:
- Integer value zero, sometimes referred to as the ASCII NUL character.
- Characters whose integer representations are in the range from 1 through 31, except for alternate streams where these characters are allowed. For more information about file streams, see File Streams.
- Any other character that the target file system does not allow.
- Use a period as a directory component in a path to represent the current directory, for example ".\temp.txt". For more information, see Paths.
- Use two consecutive periods (..) as a directory component in a path to represent the parent of the current directory, for example "..\temp.txt". For more information, see Paths.
- Do not use the following reserved device names for the name of a file:
CON, PRN, AUX, NUL, COM1, COM2, COM3, COM4, COM5, COM6, COM7, COM8, COM9, LPT1, LPT2, LPT3, LPT4, LPT5, LPT6, LPT7, LPT8, and LPT9. Also avoid these names followed immediately by an extension; for example, NUL.txt is not recommended. For more information, see Namespaces.
- Do not end a file or directory name with a space or a period. Although the underlying file system may support such names, the Windows shell and user interface does not. However, it is acceptable to specify a period as the first character of a name. For example, ".temp".
Short vs. Long Names
A long file name is considered to be any file name that exceeds the short MS-DOS (also called 8.3) style naming convention. Typically, Windows stores long file names on disk as special directory entries, which can be disabled systemwide for performance reasons depending on the particular file system. When you create a long file name, Windows may also create a short 8.3 form of the name, called the 8.3 alias, and store it on disk also. This 8.3 aliasing can be disabled for a specified volume. http://www.records.ncdcr.gov/erecords/filenaming_20080508_final.pdf
Rule #1: Avoid using special characters in a file name. \ / : * ? “ < > | [ ] & $ , .
The characters listed above are frequently used for specific tasks in an electronic environment. For example, a forward slash is used to identify folder levels in Microsoft products, while Mac operating systems use the colon. Periods are used in front of file-name extensions to denote file formats such as .jpg and .doc; using them in a file name could result in lost files or errors.
Rule #2: Use underscores instead of periods or spaces.
As mentioned above, periods already have a specific function in a file name, which is to tell the computer program where the file-name extension begins. Spaces are frequently translated in a Web environment to be read as “%20”. For example,
Naming tutorial.doc
would appear as
Naming%20tutorial.doc
if it were available online. This alteration can cause confusion in identifying the actual file name.
Spaces in file names can also cause broken links, because word processing tools like Microsoft Word, and e-mail clients like Microsoft Outlook, recognize spaces as an opportunity to move to another line. Therefore, a link to
\Ah1\Intranet\ar\naming conventions
could become
\Ah1\Intranet\ar\naming
conventions
Another difference that is found among operating systems and software is the acceptable length of file names. Some systems allow up to 256 characters, while others allow far fewer.
