Emojis are nothing more than tiny images (drawn, not photos) that fit in line with text, taking up the equivalent of 1 to 2 (maybe 3) character places.
They originally had, as their intent, expressing emotions much as emoticons did and do. However, the range has expanded to include so many that this can no longer be said to be the case.
Many are used as coded references to other things. The infamous eggplant emoji being the most "commonly known" one. Look it up.
Brian - Windows 10 Home, 64-Bit, Version 1809, Build 17763
A great deal of intelligence can be invested in ignorance when the need for illusion is deep.
~ Saul Bellow, To Jerusalem and Back