Files uploaded to Wikimedia Commons should have a proper name. Some things to take into account:
Names should be
- descriptive, chosen according to what the image displays or contents portray
- accurate, especially where scientific names, proper nouns, dates, etc. are used
Names should not be
- pejorative, offensive or unnecessarily crude language, as such would not be appropriate in the file description
Language, character set and extension
- Media files can be uploaded with names in any language in any script (coded as UTF-8) - see Commons:Language policy.
- Titles of media files should be meaningful and helpful in the language chosen.
- Avoid "funny" symbols (control characters, unneeded punctuation, etc.) that might be significant in future wiki markup. It is a good idea to stick to graphemic characters, numbers, underscore (space), ASCII hyphen/minus/dash, plus, and period (dot).
- The filename extension (eg .jpg) should match the file format (eg JPEG).
- When the year, date or version may be of importance, it is good to include it in the file name.
Overwriting old files
- Except for minor technical corrections, files should be uploaded under new names. The file name applies to one concrete work: do not overwrite it even with a similar image of the same subject. See Commons:Overwriting existing files.
- If a diagram or map shows the status on a given date, it should not be overwritten with the status on another date, unless in certain cases. If the file is intended to be updated, this should be noted. See Commons:Overwriting existing files#Files marked as updateable.
- File names may be up to 240 bytes long, a filename over 240 bytes may break horribly when uploading a new version (As the date is prefixed to the filename for old versions of the file which takes 15 bytes). English filenames will usually use 1 byte per character (some symbols may fall outside the ASCII character set), but for other languages, or cases with non-ASCII characters, 240 bytes may be much less than 240 characters, as these can take up to 4 bytes per character.
- Tip: Keeping the filename reasonably short reduces need for truncation when the file is downloaded, e.g. on CDs filenames are limited to 31, 64, 197 or 207 bytes or characters, depending on extensions used.
- Tip: Use the 20 first characters for essential information, as those will show up on category pages.
- Files can be renamed after they have been created, but only under some circumstances, as this breaks inbound links. It is therefore important that a good name is chosen when the file is uploaded. See Commons:File renaming.
- Commons:File renaming
- Template:Dont overwrite
- Template:Translation possible
- Commons:Overwriting existing files (a guideline)
- The limit was 255 bytes until late 2011 – see Phabricator: T32202. Existing filenames may be up to 255 bytes, but new uploads are restricted to 240.
- Phabricator: T32202