When you attach an image file to a Wiki, you can insert a thumbnail of that image directly into the Wiki’s content.
First, attach your image to the Wiki.
Next, click “Edit” and then “Insert file”.
Finally, click “Add Thumbnail image tag”.
This will add a “#thumbnail(file ID number)” tag into the Wiki’s content field, which will display the image once you save.
If you would prefer to insert the thumbnail tag manually, you can also obtain the image’s File ID here and type “#thumbnail(file ID number)” in the Wiki’s content field.
The result: