Hi In knowledge article rich text area i have multiple images i need to send these to internal websites for public visible. i found that if i ablw to change domin as community url images are visible as publicly. 
this is knowledge image url : : -- https://company--developer.sandbox.file.force.com/servlet/rtaImage?eid=ka026000000EzmV&feoid=00N2600000Db0bk&refid=0EM26000000EHHi
But i need to change like below url then only image is available to public: How can i change like this using APEX.
https://company--developer.sandbox.my.salesforce-sites.com/servlet/rtaImage?eid=ka026000000EzmV&feoid=00N2600000Db0bk&refid=0EM26000000EHHi