Journal cover images currently display only when a journal has chosen to utilize "Magazine Layout" (Configurable by selecting Admin Login in the page footer, then Edit Page, then Journal Profile.)
Cover images will be restored on the default non-magazine layout in the near future. In the meantime, journal managers and editors should continue to add journal cover imagery as they normally would, so that the cover images will be ready to display when this enhancement is in place.
Journal cover images are now displaying correctly for issues that have them. To add a journal cover to a journal issue, log into the submission management system and select Manage All Submissions > Issues > Back Issues. Select the issue you would like to add a cover image to, then select the Issue Data link near the top of the page. You'll then have options for adding a cover image, cover image caption, as well as a descriptive title & description for each issue. Return to the Table of Contents preview and select the 'Update Published Issue' button to complete your changes. Your journal issue will update on the public site within about 30 minutes.