Writes nice piece about embedded image (5)
I believe the answer is:
inset
'embedded image' is the definition.
'inset' can be an answer for 'image' (inset is a kind of image). I'm unsure of the 'embedded' bit.
'writes nice piece about' is the wordplay.
'piece' indicates a hidden word.
'about' says the letters should be written backwards.
'tesni' is hidden in the letters of 'writes nice'.
'tesni' backwards is 'INSET'.
Can you help me to learn more?
(Other definitions for inset that I've seen before include "Picture inside a larger one" , "Intimidated" , "Small diagram contained by larger one" , "Gore" , "Extra page or piece added to enlarge" .)