“The Image of Thought” is a chapter of Deleuze’s Difference & Repetition. There he argues that philosophy has been beholden to a particular simplistic model of what thinking is, and this has never been questioned (assumed to be merely part of the common sense). Deleuze attacks this markedly unphilosophical prejudice, that would see in thought something good-natured and naturally truth seeking, a mere binary play between truth and error, question and correct response. In its place he emphasizes the problematic. Thought is the development of problems; it is these problems that give sense to questions that the respondent answers in a like sense. From ‘the answer as correct = truth’, to an examination of the sense of questions, thought is placed a further step back, at the genesis of the problem that would have one ask a question in the first place.
The chapter is often recommended as an entry point to Deleuze’s own thought, and the ramifications of the arguments in the chapter resonate throughout all of his work.