There are three rhetorical gazes.  Those are: ethos, pathos, and logos.  Egos is to explain ethics to the audience.  When they use it in visuals, it is to make sense of the image.  Does it seem ethical? The second is pathos.  Pathos is to reach emotion to the audience.  For example, any image that triggers memories that can make you feel emotional.  For me, I see a spongebob squarepants quote and it automatically reminds me of my best friend at home because we quote it all the time.  Last one is logos.  Logos aims to explain logic to the audience.  It is normal to see percentage signs and statistics.

http://sites.psu.edu/rcl1213kretsingerharries/wp-content/uploads/sites/252/2013/04/On-in-Five-Poster.jpg (example of logos)

https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjVNzIwuiD-dGy43bGUFsCK_MO4lF16Hxau82Om51bgqXwAf8_SL0Ynxwaj5Dkbjmb__ggveRAsQx3zAP-PTxrfKoUEqRYxgLVZNQzDU5OXAG5_hYPvucsQoLLN3K7_me4SGhhnpvTRzFI/s1600/HaitiHelpAd.jpg (example of pathos)

http://ahs.ausd.net/modules/groups/homepagefiles/profile/1414167/85292/Image/Picture1.png (example of ethos)