Winter scene with skaters on frozen lake was executed in 1763 by well-known German landscape and portrait painter Christian Wilhelm Ernst Dietrich Dietricy (1712 Weimar-1774 Dresden). 
Full biography of Dietrich (in German) is in "Allgemeines lexikon der bildenden Künstler von der Antike bis zur Gegenwart" by Ulrich Thieme und Felix Becker , Leipzig, 1999 or in on-line Wikipedia under following link:

http://de.wikipedia.org/wiki/Christian_Wilhelm_Ernst_Dietrich

Inscription: signed Dietricy fecit (painted by ) and dated 1763 lower right.

Technique: gouache on paper, in passpartout and framed.

Measurements: only image 13 1/4" x 7 7/8"(34 x 20 cm), in passpartout and framed 19 1/2" x 14 1/4" (49,5 x 36 cm).

Condition: in good condition due to the age.