[JavaScript Error: "TypeError: style is null" {file: "chrome://zotero/content/containers/tagSelectorContainer.js" line: 608}][JavaScript Error: "[Exception... "Unexpected error" nsresult: "0x8000ffff (NS_ERROR_UNEXPECTED)" location: "JS frame :: chrome://zotero/content/zoteroPane.js :: ZoteroPane</this.updateWindow :: line 5032" data: no]" {file: "chrome://zotero/content/standalone/standalone.js" line: 87}]ZoteroStandalone</this.onLoad/<@chrome://zotero/content/standalone/standalone.js:87:7
Upload image file with the file dialog or by dragging and dropping images onto the dashed region
If so, close Zotero, go to your Zotero profile directory, move prefs.js to a temporary folder on your desktop, and restart Zotero. Does it still happen?