How long are charts and graphs stored on the server for scheduled reports?
The KEEP_EMAILED_IMAGES configuration setting specifies how many days charts and other images in scheduled reports and forwarded reports will be kept. This is for scheduled reports that use the "stored on the server" formats and forwarded reports using the HTML attachment option. The maximum is 90 days. Default is 14
Path to setting(s): Select Configuration from the navigation area > Site Configuration > Configuration Settings > and search by Key.
For more information on accessing the Configuration Editor and editing settings, refer to Answer ID 1960: Editing Configuration Settings.