Confluence builds a gallery of thumbnailed images, attached to the page, by use of the gallery macro. .
Including single images and thumbnailing them
Once images are attached to a space they may be referred to in Confluence markup.
For example, this is how we insert a thumbnailed version of a picture of the Sydney Harbour Bridge:
The thumbnailing represents a smaller version than would otherwise be represented if we showed the whole image (try clicking on the image).
Using the Gallery Macro
We've also included a macro which allows a "gallery of thumbnails" to be displayed. It is very simple to use and presents all images attached to a page in a tabulated form.
Photographs near and of the Atlassian office