According to 'exiftool' on a GNU/Linux system, the following is an 
example of EXIF metadata that is created when taking a screenshot on a 
game being playing at 1280x720 resolution on a PS3...

File Name                       : Name of Game.png
Directory                       : /path/to/directory
File Size                       : 80 kB
File Modification Date/Time     : YYYY:MM:DD hh:mm:ss-##:##
File Access Date/Time           : YYYY:MM:DD hh:mm:ss-##:##
File Inode Change Date/Time     : YYYY:MM:DD hh:mm:ss-##:##
File Permissions                : -rw-r--r--
File Type                       : PNG
File Type Extension             : png
MIME Type                       : image/png
Image Width                     : 1280
Image Height                    : 720
Bit Depth                       : 8
Color Type                      : RGB
Compression                     : Deflate/Inflate
Filter                          : Adaptive
Interlace                       : Noninterlaced
Modify Date                     : YYYY:MM:DD hh:mm:ss
Source                          : PlayStation(R)3
Title (und)                     : Name of Game
Game Title                      : Name of Game
Creation Time                   : YYYY:MM:DD hh:mm:ss-##:##
Title ID                        : BLUS#####
Image Size                      : 1280x720
Megapixels                      : 0.922