: Open the file in a text editor or use the file command in a terminal to see if the first few bytes say "JFIF" (indicating a JPEG) or something else like "HTML" or "PNG".
: Ensure your script is looking in the correct folder. Using absolute paths rather than relative ones often fixes loading issues. 3. File Naming Patterns olg003039016502020.jpg
: Many DVR systems use prefixes like "olg" or "ch" followed by a 14-digit timestamp (YYYYMMDDHHMMSS). : Open the file in a text editor