To insert an image using the Confluence editor:
At the place on the page where you want the image to appear, press <Ctrl+M>. The Insert files and images dialog box appears.
We attached an example image to this page and inserted it below, as explained in the preceding steps.
Also refer to the following Atlassian help page:
https://confluence.atlassian.com/conf613/display-files-and-images-964960698.html