Polish up an image at the point of no return (7)

I believe the answer is:

rubicon

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'the point of no return' is the definition.
(as in the phrase 'crossing the Rubicon')

'polish up an image' is the wordplay.
'polish up' becomes 'rub' (polish meaning rub to make shiny. I am not sure about the 'up' bit.).
'an image' becomes 'icon' (synonyms).
'rub'+'icon'='RUBICON'

'at' is the link.

Can you help me to learn more?

(Other definitions for rubicon that I've seen before include "cause of conflict when crossed" , "Caesar's point of no return" , "Caesar's fateful river" , "River crossed by Caesar - no turning back" , "Line fatefully gone over" .)

I've seen this clue in the Evening Standard.

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