Upload troubleshooting
A stalled upload is usually a connection issue rather than a file problem — check your connection and retry; PhotoShare resumes from where it left off rather than restarting the whole upload.
Missing metadata, most often GPS or timestamp data, isn't an upload error — it just means the original file didn't carry that data, commonly the case for screenshots, downloaded images, or photos with location services turned off at capture time. These upload successfully; they simply won't appear on the map.
If a specific file consistently fails to upload while others succeed, check that it's a supported image format and under the per-file size limit — an unusually large RAW file or an uncommon format is the most frequent cause of a persistent, file-specific failure.