[JavaScript Error: "Group with libraryID 1 does not exist" {file: "chrome://zotero/content/xpcom/data/groups.js" line: 108}][JavaScript Error: "Upload request 1/Z82NED2G failed"]
Upload image file with the file dialog or by dragging and dropping images onto the dashed region
After that, simply restarting Zotero will probably fix it. But please provide a Debug ID first.