pic vs short subject

pic and short subject both are nouns.

Word	Noun	Adjective	Verb	Adverb
pic	Yes	No	No	No
short subject	Yes	No	No	No

As nouns, short subject is a hyponym of pic; that is, short subject is a word with a more specific, narrower meaning than pic:

pic: a form of entertainment that enacts a story by sound and a sequence of images giving the illusion of continuous movement
short subject: a brief film; often shown prior to showing the feature

pic (noun)	short subject (noun)
a representation of a person or scene in the form of a print or transparent slide or in digital format	a brief film; often shown prior to showing the feature
a form of entertainment that enacts a story by sound and a sequence of images giving the illusion of continuous movement