Monet's own words on his Impression, Sunrise [Le Havre Harbour]
"Monet claimed that he titled the painting Impression, Sunrise due to his hazy painting style in his depiction of the subject: "They asked me for a title for the catalogue, it couldn't really be taken for a view of Le Havre, and I said: 'Put Impression.' [1] In addition to this explanation for the title of the work, art historian Paul Smith claims that Monet might have named the painting Impression to excuse his painting from accusations of being unfinished or lacking descriptive detail, but Monet received these criticisms regardless of the title.[6]
While the title of the painting seemed to be chosen in haste for the catalogue, the term "Impressionism" was not new. It had been used for some time to describe the effect of paintings from the Barbizon school. Both associated with the school, Daubigny and Manet had been known to use the term to describe their own works.[7]"
https://en.wikipedia.org/wiki/Impression,_Sunrise"Impressionists were
most interested in a sort of optic realism—the way light behaves in the
real world. They were among the rst artists to paint outdoors, in natural
light. They eliminated black from
their palettes, claiming there were no
true blacks in nature, and created shading
through contrasting color values.
Originally called “New Painting,” the
name “Impressionism” came from
Claude Monet’s Impression: Sunrise
(1872). Impressionists aimed to capture
the feeling of a fleeting glance, to make the painting look as if it were made
in an instant through cropped compositions and visible, dabbed brushstrokes.
The idea of the moment is perhaps best captured in Monet’s many painting
series, such as his views of Rouen Cathedral. They were made almost like a
scientific experiment; the subject and point of view were the controls, and
the light was the variable.
How to recognize Impressionism:
Contemporary social life of a middle class in the cities and suburbs,
usually at leisure, is the main subject.
The composition implies a glimpse or fleeting impression of
a scene.
Painters experimented with varying elements such as light
and viewpoint.
Painters had a fascination with the effects of light and color.
Painters observed nature in natural light; there are no blacks and no
chiaroscuro shading.
Figures and objects have no outlines; contrast of color and value
create shapes instead.
Compositions are cropped: partial figures, unusual points of view
above or below the scene, awkward poses suggesting imminent
movement.
Paint is applied in in short dabs of color."
-Sharon Latchaw Hirsh, President of Rosemont College
Dr. Hirsh is an internationally recognized scholar of Western European art
at the turn of the 20th century. She was a visiting curator at the Montreal
Museum of Fine Arts and at the Swiss Institute for Art Research. Dr. Hirsh
has served as a senior fellow at the Center for Advanced Studies in the Visual
Arts at the National Gallery of Art, Washington; she has also been visiting
scholar at the University of Colorado, the Swiss Institute for Art Research,
and the Art Institute of Chicago.
Here is a clear description, from a known source, that lets people figure out for themselves if the photo can be considered in the impressionistic style.