Steps to follow:

• Find an image that you like as a source for your color palette
• Open Adobe Color
• Drag and drop your image into the specified box.
• Choose the color mood
  • colorful
  • bright
  • muted
  • deep
  • dark
• Name the color palette and export it by using "Publish theme" and "Save".
• Take a screen shot.
• Open Midjourney.
• Past your image into the prompt box and hit "Enter".
• Right click the image and use the picture link.
• Include an --sref prompt