If the image itself contains written text, you can use a tool like Google Lens or an OCR scanner to convert the visual text into editable text.
If you are looking for a specific description of what "IMG_3811" typically represents in a certain context (like a famous viral photo or a specific document leak), please provide more details about where you encountered the file.
You will need a utility like WinRAR , 7-Zip (Windows), or The Unarchiver (macOS) to open the archive.