Here's my rough service workflow:
Only texts can be added, and a new note is created.
Apple Script:
on run {input, parameters}
tell application "System Events"
tell process "Notes"
click menu item "New Note" of menu "File" of menu bar 1
click menu item "Paste" of menu "Edit" of menu bar 1
end tell
end tell
return input
end run
Update*2:
To add pictures, simply use another Apple Script block that clicks a menu item. And add some delay for Notes app to launch.
on run {input, parameters}
tell application "System Events"
tell process "Google Chrome"
click menu item "Copy" of menu "Edit" of menu bar 1
end tell
end tell
return input
end run