Updated: Feb 2
MediaWiki File Upload Restrictions
MediaWiki configuration may restrict your ability to upload files:
by file size (defaults to 2Mb)
by file type (defaults to popular image formats: [ 'png', 'gif', 'jpg', 'jpeg', 'webp', ])
A warning about current settings are shown in Special:Upload – a standard MediaWiki interface for files uploading.
Both values can be adjusted to your particular wiki by administrators or developers in config files.
Uploaded files may have copyright implications and require an appropriate attribution. Each file has its own page that can be edited like any regular wiki page, so say your kudos to the file authors / creators there. The list of licenses can be adjusted to your needs on Mediawiki:Licenses by users belonging to the interface administrators group. If you are unfamiliar with MediaWiki User Groups, you can read more about them here.
Standard File Upload Workflow
The standard MediaWiki file uploading is done via the Special:Upload on the wiki. Its interface allows:
to select a file in your computer filesystem: Source filename
to adjust the file name: Destination filename
to input the text that will be preloaded to the file page: Summary
to choose the license, if necessary: Licensing
to force uploading even if duplicates are found: Ignore any warning
MediaWiki File Page
Once you click the Upload file button, a page with the preloaded text and the image preview will be created. The page also contains:
a link for re-uploading the file,
a table with the history of file versions,
a list of pages that reference this file,
an expandable section with the file metadata