The recent exponential growth in the use of image processing software applications has been accompanied by a parallel increase in their use in criminal activities. Image processing tools have been associated with a variety of crimes, including counterfeiting of currency notes, cheques, as well as manipulation of important government documents, wills, financial deeds or educational certificates. Thus, it is important for the Document Examiner to keep up to date with latest technological and scientific advances in the field. The present research focuses on the use of image processing tools for the examination of computer-manipulated documents. The altered documents were examined using a suite of currently available image processing tools. The results demonstrate that a number of tools are capable of detecting computer-based manipulations of written documents.