Thin album's rough and ready portrait (9)
I believe the answer is:
thumbnail
'ready portrait' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how one could define the other.
'thin album's rough' is the wordplay.
'rough' indicates an anagram (a rough or broken ordering of the letters).
'thin'+'album'='thinalbum'
'thinalbum' is an anagram of 'THUMBNAIL'.
'and' acts as a link.
Can you help me to learn more?
(Other definitions for thumbnail that I've seen before include "Kind of sketch r" , "Small image" , "This digital-type sketch is brief and concise" , "type of sketch" , "Particular sketch" .)