(PHP 4 = 4.0.1)
The read_exif_data() function reads the EXIF headers from a JPEG image file. It returns an associative array where the indexes are the Exif header names and the values are the values associated with those Exif headers. Exif headers tend to be present in JPEG images generated by digital cameras, but unfortunately each digital camera maker has a different idea of how to actually tag their images, so you can't always rely on a specific Exif header being present.