Sorry, figured anyone here would probably be a long term user and likely have that experience. Quick guide (it's easy enough):
- There's an option, "Upload file", on the sidebar to the left. Click it.
- Choose the file to upload, and the name to give it (often the same, but you can change it). Give a brief description -- on the major reference wiki's there's a lot to go here, but for this one a brief note will do.
- Click the button to upload it.
- The image will appear once uploaded, on a "File:" page, eg "File:Mypicture.jpg".
- Include it as follows (simple usage):
- To include full size: [[File:Mypicture.jpg]] (As simple as that)
- To inclue it as a small "thumbnail" with a caption, that can be clicked for the full image: [[File:Mypicture.jpg|thumb|position|size|This is my picture.]]
where position is left/center/right, size is usually in pixels (enter as 200px, 400px, etc) and the rest is a caption.
Hope that helps.