The artist for this miniature portrait painted on porcelain is unknown, but the sitter is Emperor Franz-Josef of Austria. It to be appears based upon one of the three large oil portrait images as below which were all painted circa 1848, but by different artists.
They are all slightly different in his decorations and his pose, with the third of the three image best fitting the miniature portrait. The miniature has a tiny, but illegible, monogram at the upper left, which is probably that of the artist, the portrait and frame being far better quality than the normal run of what are often described as decorative miniatures.
Franz-Joseph (18 August 1830 – 21 November 1916) was Emperor of Austria and Apostolic King of Hungary from 1848 until his death in 1916. From 1 May 1850 until 24 August 1866 he was President of the German Confederation.
In December 1848, his predecessor Emperor Ferdinand of Austria had abdicated the throne as part of Ministerpräsident Felix zu Schwarzenberg's plan to end the Revolutions of 1848 in Austria, which allowed Franz Joseph, as Ferdinand's nephew, to ascend to the throne. 1479
Elsewhere in this Artists and Ancestors collection, there is this unfortunately "rubbed" miniature portrait of Ferdinand, which needs restoration by a more competent artist than me! See Theer, Robert - portrait of Ferdinand I of Austria
There is also a miniature portrait of an earlier Emperor. It is attributed to Antonio Bencini and is of Joseph II (1741-1790) Emperor of Austria.
He was the son of Maria Theresa and a brother of Marie Antoinette. See
Bencini, Antionio - portrait of Joseph II