This may happen when the Auto Portrait Framing, Auto Object Framing or Auto Dual Rec feature is switched on.
Auto Portrait Framing or Auto Object Framing
When these functions are set to Auto, the camera automatically trims the images you take into optimal compositions, and then saves them.
This means that two images will be saved in the camera: the original image and the trimmed one.
The automatically saved image has one of the below indications in the upper left corner of the LCD screen:
These functions are activated when the camera detects faces, subjects for macro shooting, or subjects tracked by Lock on AF.
NOTE: While using the Auto Port. Framing function, the camera detects human faces only.
Auto Dual Rec
When this function is set to On, the camera automatically saves still images during movie recording. This function is activated when impressive compositions containing people are detected.