Pictograms can be simplified and abbreviated to the point where some would not be able to see the "picture." 
Seeing any picture requires some learning. Anthropologists have recorded that tribes unfamiliar with two dimensional representation were not able to initially recognize the objects in a photograph. There is a translation or mapping involved. One has to "get" or acquire the concept before one "sees" the similarity in a partial representation. It has been argued that all pictures represent post linguistically or post conceptually. Visual literacy is something that one acquires not something that is there from the beginning.
Not all decorative marks on a page are icons ("eye" cons) or representations. Ornaments such as bullets and diamonds do not refer to something else, they simply mark a list. Even dingbats and decorations resembling snowflakes and flowers are not iconic unless they are used referentially. 
Language has been called a graveyard of dead metaphors. Letters and could be called a graveyard of dead pictograms.
Most logograms, such as @, %, &, #, began as abbreviations.
Picture writing, one interpretation of pictography, has never quite worked. It is certainly a misnomer for Hieroglyphics where pictorial semagrams were usually used primarily as determinants to clarify the meaning of iconic phonograms.
Bliss Symbolics is the most complete attempt to develop a writing system based mostly on non-phonographic simplified pictures. 
Keyboard symbolics have been used to in mental institutions to enable patients with language disabilities and speach disorders to communicate. Similar picture or symbol keyboards have been used to teach animals to communicate. 

    Some have speculated that the ANKH symbol began as a representation of a sandal strap which had the same first syllable as the word for LIFE. *Ankh also referred to a mirror and mirrors were often designed in the shape of the ANKH symbol. 

    The connection between an ideogram and its reference is not arbitrary but the connection can be obscure. 
Ideograms are often used as a generic term for any non-arbitrary sign. As defined here, the reference of such a pictorial sign is not the thing pictured but an associated idea -- often an abstract idea that cannot be pictured. Examples include a dove for peace and an owl for wisdom. 

    Ideograms come the closest to the Jungian idea of a symbol as a representation that has meaning and connotations beyond the obvioius -- beyond their use as a simple sign. 
    A word or an image is symbolic when it implies something more than its obvious and immediate meaning. Symbols often aquire connotations in a cultural context making it difficult for an outsider to fully grasp the full significance of something like a Cretan double headed ax or an Egyptian amulet such as the wadjet (eye of Horus). 
    An image, word, or name is symbolic when it embodies a rich aura of connotations that extend beyond its conventional and obvious meaning. Symbol- ism is often used to describe the undescribable. This is why all religions employ imagery and symbolic language. According to Jung and others, man uses symbolic terms to represent concepts that are beyond his intellec tual capabilities to define or fully comprehend. 

he symbol or conventional sign, commonly referred to as a letter, that stands for a monosyllable or the initial sound in a monosyllable. Some letter names are not acrophonic. The referenced sound is not the initial but the ending sound. Examples: em, es.Some English letter names do not contain the letter's sound. e.g., aitch, double-ewe, wie.

    The owl, Mer in Egyptian, was associated with the letter found on its head, the M. In most pictographic scripts, the letters look something like their names and each letter name begins with the signified sound. The letter M looks like the ears of a MeR (Coptic: mouri) and sounds like the initial sound in its name /m/.
Types: Vowels and Consonants
Speech sounds are divided into vowels and consonants. When the breath channel is constricted at one or more points the sound is called a consonant. When the channel is not blocked or constricted enough to cause audible friction, the sound is called a vowel. Consonants are further classified in terms of the friaction points: labials: p/b, dentals: t/d .... Vowels are classified high-low and front-back.