The image showed a small boy wearing a "47" shirt, and posters explicitly compared the child to Holocaust victims:
This little boy, who has been taken from his parents, has been assigned a number. #47 on his chest and arm. Like the Holocaust. •••••••••••••••••••••••••• The Keep Families Together Act S-3036 has the support of All Democrats EXCEPT Claire McCaskill (D-MO) 202-224-6154; Joe Donnelly (D-IN) 202-224-4814; Joe Tester (D-MT )202-224-2644; Doug Jones (D-AL)202-224-4124; Heidi Heitkamp (D-NV) 202-224-2043; Joe Marchon (D-WV) 202-224-3954. At this point, NOT ONE Republican has signed on to this bill that would prohibit children from being separated from their parents. PLEASE CALL your members of Congress. 202-224-3121. Look at this image. It should send chills up your spine. We must not let history repeat itself. We must speak loud and clear. #Wherearethechildren
It appears that a complete version of the photograph appeared with a 16 June 2018 New York Times opinion editorial titled "You Can’t Be Pro-Life and Against Immigrant Children." A caption for the photograph simply said:
A boy and father from Honduras being taken into custody by United States Border Patrol agents near the Mexico border on Tuesday.
A closer look at the image shows that the numbering is part of the shirt:
A separate article published by another outlet provided a similar description for a photograph clearly from the same set of images:
U.S. Border Patrol agents take into custody a father and son from Honduras near the U.S.-Mexico border on June 12, 2018, near Mission, Texas. The asylum seekers were then sent to a processing center for possible separation.
The photographs showed Border Patrol agents taking in a father and son, neither of whom had yet been processed. The snapshot was captured as the pair were apprehended, meaning they had not been issued clothing. The uncropped images show a shirt manufactured for retail, not government issue.