The Victorian Era spanned from 1837 to 1901 during the reign of Queen Victoria. During her 64 year reign womens' dress styles changed every decade it seems. The above image quickly illustrates the differences in Victorian dress change, most notably the shape of the skirt. Towards the end of the Victorian era we enter into the style sometimes referred to as Gibson Girl fashion. (I'll do a post on that another day). The Edwardian Era followed the Victorian era during the reign of Prince Edward.
The dresses started off quite full with caged crinolines (1840s-1850s) and dresses were bell shaped, and towards the end of the Victorian era the dresses became more narrow with cuirasse bodices and bustles (1870s-1890s).
Victorian fashion plate dating from 1874
Victorian Afternoon dress c.1864 + Claude Monet's 'Women in the Garden' c. 1866
Image Credits: Silhouettes from Enchanted Serenity Period Films. All other images from Historical Fashion and F Yeah Victorians. Victorian afternoon dress via Defunct Fashion, Claude Monet 'Women in the Garden' from Musee d'Orsay via Historical Fashion
Additional Resources for Victorian Fashion:
Abiti Antichi - Brief History of Fashion (Italian site)
Early Victorian Fashion - Fashion-Era.com
Victorian Fashion - Wiki