For contemporary influences, the imagists studied the French symbolists, who were experimenting with free verse (vers libre), a verse form that used a cadence that mimicked natural speech rather than the accustomed rhythm of metrical feet, or lines.
Rules of rhyming were also considered nonessential.
The ancient form of Japanese haiku poetry influenced the imagists to focus on one simple image.
Greek and Roman classical poetry inspired some of the imagists to strive for a high quality of writing that would endure.
T. E. Hulme is credited with creating the philosophy that would give birth to the Imagism movement.
Although he wrote very little, his ideas inspired Ezra Pound to organize the new movement. Pound’s “In a Station of the Metro” is often given as one of the purest of his imagist poems.
Amy Lowell took over the leadership role of the imagists when Pound moved on to other modernist modes.
Her most anthologized poems include “Lilacs” and “Patterns.”
Other important imagist poets include Hilda Doolittle, whose poem “Sea Poppies” reflects the Japanese influence on her writing, and her “Oread” is often referred to as the most perfect imagist poem. 1
(some of the posts with imagist poems can be found here, here, here, and here.) 
Oh it's a long long while from May to December
But the days grow short when you reach September
When the autumn weather turns leaves to flame
One hasn't got time for the waiting game
Oh the days dwindle down to a precious few
September November and these few precious days I'll spend 
with you
These precious days I'll spend with you.
