Real photo postcard postmarked August 19, 1910 at Newton, Iowa, showing Jesse William Greenlief at age 5 months; addressed to Miss Mary Hughes at 738 West 20th Street, Des Moines, Iowa.
From brief online research, hopefully correct - corrections and additions requested - while respecting the privacy of living or recently deceased people:
Jesse William Greenlief was born March 9, 1910 at Newton Township, Iowa, the son of Charles E. Greenlief and Jomattie Ellen (Rumbaugh) Greenlief; their fifth child. The postcard notes "This is Gracie's Brother". Gracie was Delta Grace Greenlief, born in 1899, presumably Mary Hughes was Grace's friend or caretaker.
On July 21, 1929 at Huntington Park, Los Angeles, California, Jesse married Marjorie Elizabeth Castner, also an Iowa native, born October 16, 1910 at Union Township, daughter of James Miller Castner and Lucile (Morrisey) Castner. Another record, from California, County Birth, Marriage, and Death Records, 1849-1980, gives the date as July 23, 1929. At the time they were both living at Long Beach, California. They would have at least two children, a daughter and son. U.S. Censuses show that they lived in the Los Angeles, California area and at Seattle, Washington.
Jesse died at Toronto, Ontario in 1974; Marjorie died in 1984. They're buried in the Carling Cemetery at Carling, Ontario, Canada. Jesse's Social Security death record gives his address as the U.S. Consulate, but I don't know if that means he worked there or if they handle the deaths of U.S. residents in Canada.
I don't know the identity of Miss Mary Hughes but note that there was a Mary Hughes, born about 1903, who is enumerated in the 1910 Census as living on 20th Street in Des Moines, the daughter of Ernest M. Hughes and Edith (Todd) Hughes. If this Mary was the recipient of the postcard, she would have been about age 7 at the time, not out of the ordinary.
If you have corrections and/or additions to the information above, or an identity for Miss Mary Hughes, please leave a comment or contact me directly. Please be careful when mentioning living or recently deceased people.