She died in 1761 so this is a posthumous portrait. The core of her Wikipedia article follows: "On 5 February 1735, Elisabeth married Duke Charles Louis Frederick of Mecklenburg-Mirow (23 February 1707 – 5 June 1752) at Eisfeld, the youngest son of Adolphus Frederick II, Duke of Mecklenburg-Strelitz, and half-brother to Adolphus Frederick III. They became the parents of ten children.
The death of her childless brother-in-law on 11 December 1752, six months after she was widowed, left Albertine as regent of both men's duchies on behalf of her eldest son, Adolphus Frederick IV, until he attained his majority at the age of 14 on 17 January 1753. During that brief period she ruled the Strelitz duchies under the protection of George II of Great Britain, warding off encroachments from Duke Christian Ludwig II, ruler of the Schwerin branch of the House of Mecklenburg.
She died in 1761, shortly before the marriage of her daughter Sophia Charlotte to the Prince of Wales, and was buried at the ducal crypt in Mirow.”
Six of her children reached adulthood. I could not find another portrait of her. She may have been so busy bearing children that she lacked time to sit for artists.
From artoftherococoera.tumblr.com; spots in background removed and the image trimmed with Photoshop.