wichita.edu
…to write out the entire text in another application (Word, Pages, WordPad, TextEdit, etc.) and, once finished, copy/paste it into the Alternative description field. Once Save is selected the ALT-Text is attached to the image. Note: The Insert/Edit Image settings box will NOT let you apply an image until there is ALT-Text in the "Alternative description"…
https://www.wichita.edu/services/mrc/Web_Services/alttext_guide.php