Jack Kirby: First Love Illustrated #68 - September 1956

Sep. 1956: First Love Illustrated #68

Jack Kirby: Black Cat Mystic #58 - September 1956

Jack Kirby: True Bride-To-Be Romances #19 - August 1956

Aug. 1956: True Bride-To-Be Romances #19

Jack Kirby: Hi-School Romance #54 - August 1956

Aug. 1956: Hi-School Romance #54

Jack Kirby: First Romance #41 - August 1956

Aug. 1956: First Romance #56

Jack Kirby: First Love Illustrated #67 - August 1956

Aug. 1956: First Love Illustrated #67

Jack Kirby: Young Love #71 - June/July 1956

June-July 1956: Young Love #71

Jack Kirby: Young Romance #83 - June/July 1956

June-July 1956: Young Romance #83

Jack Kirby: Young Brides #28 - May/June 1956

May-June 1956: Young Brides #28

Jack Kirby: Young Love #70 - April/May 1956

April-May 1956: Young Love #70

Jack Kirby: Young Romance #82 - April/May 1956

April-May 1956: Young Romance #82

Jack Kirby: True Bride-To-Be-Romances #17 - April 1956

Apr. 1956: True Bride-To-Be Romances #17

Jack Kirby: Young Brides #27 - March/April 1956

Mar.-Apr. 1956: Young Brides #27

Jack Kirby: Love Problems and Advice Illustrated #38 - March 1956

Mar. 1956: Love Problems and Advice #38

Jack Kirby: Young Love #69 - February/March 1956

Feb.-Mar. 1956: Young Love #69

Jack Kirby: Young Romance #81 - February/March 1956

Feb.-Mar. 1956: Young Romance #81

Jack Kirby: Black Cat Mystery #57 - January-March 1956

Jan.-Mar. 1956: Black Cat Mystery #57

Jack Kirby: Warfront #28 - January-March 1956

Jan.-Mar. 1956: Warfront #28

Jack Kirby: Young Brides #26 - January/February 1956

Jan,-Feb. 1956: Young Brides #26

Jack Kirby: Young Romance #80 - December 1955/January 1956

Jack Kirby: Western Tales #31 - October 1955

Oct. 1955: Western Tales #31

Jack Kirby: Police Trap #6 - September 1955

Sept. 1955: Police Trap #6

Jack Kirby: I Love You #7- September 1955

Sept. 1955: I Love You #7

Jack Kirby: Foxhole #6 - September 1955

Sept. 1955: Foxhole #6 

Jack Kirby: From Here to Insanity #11 - August 1955

Aug. 1955: From Here to Insanity #11

Jack Kirby: Bulls Eye #7 - August 1955

Aug. 1955: Bulls Eye #7

Jack Kirby: Police Trap #5 - July 1955

July 1955: Police Trap #5

Jack Kirby: Foxhole #5 - July 1955

July 1955: Foxhole #5

Jack Kirby: Charlie Chan #6 - June 1955

June 1955: Charlie Chan #6

Jack Kirby: Bulls Eye #6 - May 1955

May 1955: Bulls Eye #6

Jack Kirby: In Love #5 - May 1955

May 1955: In Love #5

Jack Kirby: Fighting American #7 - April/May 1955

Apr.-May 1955: Fighting American #7

Jack Kirby: Foxhole #4 - April 1955

Apr. 1955: Foxhole #4

Jack Kirby: Win A Prize #2 - April 1955

Apr. 1955: Win A Prize Comics #2

Jack Kirby: Bulls Eye #5 - April 1955

Apr. 1955: Bulls Eye #5

Jack Kirby: Police Trap #4 - February/March 1955

Feb.-Mar. 1955: Police Trap #4

Jack Kirby: Fighting American #6 - February/March 1955

Feb.-Mar. 1955: Fighting American #6

Jack Kirby: Foxhole #3 - February 1955

Feb. 1955: Foxhole #3

Jack Kirby: WIn A Prize #1 - February 1955

Feb. 1955: WIn A Prize Comics #1

Jack Kirby: Bulls Eye #4 - February 1955

Feb. 1955: Bulls Eye #4

Jack Kirby: In Love #3 - January 1955

Jan. 1955 - In Love #3

Jack Kirby: Police Trap #3 - December 1954/January 1955

Dec. 1954-Jan. 1955 - Police Trap #3

Jack Kirby: Fighting American #5 - December 1954/January 1955

Dec. 1954-Jan. 1955: Fighting American #5

Jack Kirby: Bulls Eye #3 - December 1954/January 1955

Dec. 1954-Jan. 1955: Bulls Eye #3

Jack Kirby: Foxhole #2 - December 1954

Dec. 1954: Foxhole #2

Jack Kirby: Black Magic #33 - November/December 1954

Nov.-Dec. 1954: Black Magic #33

Jack Kirby: Police Trap #2 - October/November 1954

Oct.-Nov. 1954: Police Trap #2

Jack Kirby: Foxhole #1 - October 1954

Oct. 1954: Foxhole #1

Kirby's cover image is believed to have been based on Joseph Hirsch's "High Visibility Wrap" painting that appeared in the 1945 book Men Without Guns. 

1945: Joseph Hirsch's High Visibility Wrap 

And in The Secret History of Marvel Comics it's noted that the Hirsch image appeared on the cover of Martin Goodman's June 1951 Stag magazine.

1951: Stag v. 2 #1 

Sources: 
http://kirbymuseum.org/blogs/dynamics/2010/06/17/foxhole-1-cover/

Bell, Blake and Dr. Michael J. Vasallo. The Secret History of Marvel Comics: Jack Kirby and the Moonlighting Artists of Martin Goodman's Empire, 2013 (84).