Avoid using the File Download Servlet to reference static resources
Impact area
Manageability
Severity
Medium
Affected element
Apex Page
Rule ID
SF-0135
Impact
Images should be included in APEX pages through static resources. Using the Download servlet url is less efficient from a performance point of view and is also typically associated with a hardcoded sysid.
Remediation
Use static resources to serve JavaScript files, as well as images, CSS, and other non-changing files. JavaScript and other assets served this way benefit from the caching and content distribution network (CDN) built into Salesforce.
Time to fix
30 min