Reply To: Some Edits on my Theme

sorry but the photos you shared is not working –> all the images Broken
To do it specifically for the Pages or Categories, you need to edit that respective Page or Category individually one by one > and when you scroll down a bit you will find the option to upload a specific Image.

See these images for reference:
https://ibb.co/d4KmPRn (For Category)
https://ibb.co/5nv0K7V (For Page)