To use an image or sound file on Engineering wiki, you should upload the file to the wiki where you want to use it.
Click on Upload file in the sidebar of the correct wiki to upload a file. You must be logged in to do this. Browse to where the file is on your computer. In the "summary" box, write a description of the image, who took it, and what license it is available under (GFDL, Public Domain, etc). This information will be placed on the file description page, along with a history of modifications to the image. When MediaWiki 1.5 is released, automatic image meta data will also appear on this description page. This is automatical extracted from uploaded images.
File types that can be uploaded include .png, .gif, .jpg, .jpeg, and .ogg. For security reasons, many file types may not be uploaded and will not be added to the whitelist. This includes HTML and Zip files.
Uploaded images can be used inline on a page, linked to, included in a gallery, or automatically thumbnailed. See MetaWikipedia:Help:Images and other uploaded files for full details.
When a file is uploaded with the same name as an existing one, the old one is replaced.
From MediaWiki 1.5, you will be able to specify a different filename when uploading files rather than needing to upload the file with the name you saved it as on your own computer.