There is still no clear answer to the question what is the difference between icons and pictograms, and what exactly should be called an icon and a pictogram. Some people call these two concepts signs/characters. Usually the following is accepted when working on projects for convenience, understanding and effective communication: a pictogram is a two-dimensional monochromatic image of a small size, which usually supplements or replaces the name of the item that it specifies. “Icon” term refers more often to a two- or three-dimensional color image, visually more developed, which often supplements the visual image of a page, section, etc.
Usage of a pictogram will be an effective solution if you are limited by space and User’s time, which often happens when developing mobile application design, when in need to duplicate or replace the website menu items, etc. It will facilitate the interface perception, increase the operation speed, help improve the applications’ usage and save the User’s time due to its visual simplicity and familiarity.
Icons are used to style a project, ease the information perception, create the User’s pleasant visual sensations, prompt the User to perform a particular action, increase the User’s preference to a project (marketing experts like to call it an “increase in brand loyalty”). Icon design is due in no small part to this.