How do i write an API for updating/ upload Company Logo and Login background image?.
API
You don't have to write and API to do that function as its already built in. Login to the SCP, --> Settings --> Company and then the two tabs for Logos' and Login Backdrop. The Login Backdrop is only for the SCP panel at this point. They are talking about making it easier for themes and customization inversion 2.0.
can we post a request externally for uploading a Company Logo?.
For that you need to create a separate API using PHP. Provide some more brief how you will call (from which system) this api to update the company logo. Let me know if you need more help to create api.
https://github.com/sharmaghanshyam