Adding your own logo is very easy but may require a little CSS editing if you would like to use a different sized logo to the default.
Replacing the current image:
- Open your start page (your-site.wikidot.com/start).
- Click on files.
- Upload your logo.png (it must have this name).
Editing the wiki's CSS to adjust for size:
- Open themes (on your wiki) and follow the instructions there.