Sessions OnlyKeeps a record of each time you start or quit Photoshop and each time you open and close files (each image’s filename is included). Does not include any information about edits made to the file.
ConciseIncludes the text that appears in the History panel in addition to the Sessions information.
DetailedIncludes the text that appears in the Actions panel in addition to the Concise information. If you need a complete history of all changes made to files, choose Detailed.