[JavaScript Error: "this.noteField.onInit is not a function" {file: "chrome://zotero/content/bindings/noteeditor.xml" line: 76}]
Upload image file with the file dialog or by dragging and dropping images onto the dashed region
https://www.zotero.org/support/reporting_problems#provide_steps_to_reproduce
(Spanish is fine, but we need more info on what you're doing.)