Some programs generate and save simple one-line file descriptions in special, and quite non-standardized, files located in the same folders as the files being described. These files are generally have names like descript.ion, 0index.txt, files.bbs etc. Use Information | Data Import/Export | Export Descriptions and Import Descriptions to create such files or to bring the information from such files into pictures' standard picture information. During export, you can choose whether to use the Title or Description field as the description.
If the pictures already had description files, these will be overwritten by your export. If you check the Preserve remaining files' descriptions box, then the descriptions for any pictures in the folder that were not selected will be kept as-is; otherwise, they will be thrown away.
If you turn on Give exported file Hidden attribute, then the file will receive the Hidden file attribute. This will make it invisible to most programs.