His photographs include the iconic picture of Isambard Kingdom Brunel which was part of a commission by the London-based weekly newspaper Illustrated Times[7][8] to document the construction of the world's largest steamship, the SS Great Eastern.

[9][11] Howlett made photographic studies for the artist William Powell Frith to assist him on his vast modern panorama painting The Derby Day (1856–58; Tate, London) which was exhibited at the Royal Academy of Arts in 1858.

His death was apparently due to typhoid (rather than as a result of over-exposure to dangerous chemicals, as was suggested by some at the time, a myth that has continued to this day).

[3][9] He also designed and sold 'dark room tents'[3] and worked in partnership with Joseph Cundall[3][10] at "The Photographic Institution" at 168 New Bond Street, London.

[2] These included copying the works of Raphael for Prince Albert, and making a series of portraits of heroic soldiers from the Crimean War.

[2][b] In 2004 Cundall and Howlett's portraits of Crimean war veterans, were used by the Royal Mail for a set of six postage stamps to mark the 150th anniversary of the conflict.

[2] Howlett's major work was the commission by The Illustrated Times Weekly Newspaper[7][8] to document the construction of the world's largest steamship, the SS Great Eastern.

[2] This project included the well-known portrait of the Great Eastern's creator and engineer, Isambard Kingdom Brunel, standing in front of the giant launching chains on the 'checking drum' braking mechanism at John Scott Russell's Millwall shipyard.

Howlett died in 1858, aged 27, at his home and studio at 10 Bedford Place, Campden Hill, shortly after returning from a trip to France to try out a new 'wide angle lens'.

[1] The cause of death was apparently due to typhoid, rather than (as suggested by some at the time) to over-exposure to the chemicals used in the Collodion photographic process invented by Frederick Scott Archer in about 1850.