: This is typically a timestamp or a unique ID. If it's a Unix timestamp, 1551547128 translates to approximately March 2, 2019 , at 5:18 PM UTC.
: Often used to denote a sequence or version (e.g., the first image in a set). post_28_IMG_1551547128_1.jpeg
: The file extension for the Joint Photographic Experts Group format, a common lossy compression method for digital images. Working with JPEG Files : This is typically a timestamp or a unique ID