Commons:File naming

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Files uploaded to Wikimedia Commons should have a proper name. Some things to take into account:

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.
  • File names may be up to 240 bytes long[1], 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.[2]
    • Tip: Keeping the filename reasonably short reduces need for truncation when the file is downloaded, e.g. on CD:s 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.

See also[edit]


  1. The limit was 255 bytes until late 2011 - see Bugzilla30202. Existing filenames may be up to 255 bytes, but new uploads are restricted to 240.
  2. Bugzilla30202