(3)(+0000002): Integration: Instantiating @zotero.org/Zotero/integration/application?agent=WinWord;1 for command addEditCitation with doc C:\Users\[…]\[…].docx(4)(+0000028): ZoteroWinWordIntegration: getDocumentData(3)(+0000015): {better-bibtex startup: [translators]} +8335 window-loaded: chrome://zotero/content/integration/progressBar.xul(3)(+0000009): Moving window to 332, 321
Upload image file with the file dialog or by dragging and dropping images onto the dashed region
Restart Zotero and try again, and if you're still having trouble, check to make sure that the dialog isn't just appearing behind the main Zotero window.
If you can't figure it out, restart Zotero and provide a Debug ID for an attempt that fails.
You should also try disabling third-party plugins.