Brief article largely altered in album (9)
I believe the answer is:
thumbnail
'brief' is the definition.
(thumbnail can mean a brief or summary)
'article largely altered in album' is the wordplay.
'article largely' becomes 'th' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'altered' indicates anagramming the letters.
'in'+'album'='inalbum'
'inalbum' anagrammed gives 'umbnail'.
'th'+'umbnail'='THUMBNAIL'
(Other definitions for thumbnail that I've seen before include "Sort of sketch" , "small picture" , "This sketch is short and concise like manual appendage" , "Small sketch" , "Brief or concise representation" .)