Image-obsessed female maybe changing a lot into one frock (10)
I believe the answer is:
idolatress
'image-obsessed female maybe' is the definition.
(an idolater worships images or idols)
'changing a lot into one frock' is the wordplay.
'changing' indicates anagramming the letters.
'into' means one lot of letters goes inside another.
'one' becomes 'I' (roman numeral).
'frock' becomes 'dress' (synonyms).
'a'+'lot'='alot'
'alot' with letters rearranged gives 'olat'.
'i'+'dress'='idress'
'olat' inserted within 'idress' is 'IDOLATRESS'.
(Other definitions for idolatress that I've seen before include "She greatly admires" , "woman obsessed by her image" , "Female associated with false image" .)