What is the relationship of pictographs and cuneiform signs?

Answer 1

Cuneiform signs (which were invented by the Sumerians of Mesopotamia--NOT the Egyptians--and borrowed by the Semitic people who settled there later, including the Babylonians) BEGAN as pictographs, something like this.

1) A simplified picture of some thing would represent the Sumerian word for that object

2) Since most Sumerian words are just one syllable long, the same sign ALSO came to be used for that syllable, or syllables very close to it.

Thus the cuneiform system that developed was a combination of logograms** (signs standing for words) and syllabic signs. When the system was borrowed by the Semitic peoples and then others, the use of syllables pre-dominated.

**For what it's worth, we use some logograms in English and other European langugages, esp. the Arabic numerals, since each is read as the equivalent number-word in each language.

Answer 2

Well pictographs are graphs using pictures and cuneiform is a form of egyptian writing that used picture symbols.

Answer 3

pictographs evolved in some cultures to represent words, see kanji