Mechanisms are provided for generating alternative text descriptions for images in electronic documents. An original image embedded in an electronic document is analyzed to generate a data pattern for the image. A matching operation is performed to identify similar images in other electronic documents from sources of electronic documents based on the generated data pattern. Textual description information associated with the similar images is extracted from data associated with the similar image. An alternative text description for the original image is generated based on the extracted textual description information associated with the similar images. The alternative text description for the original image is stored in association with the original image.