The first image shows a rectangle and a dotted line that divides the image in two parts via the rectangle's diameter.
Although the line divides the rectangle in two equal parts, it is NOT a line of symmetry, because such definition requires to be the line that provides a mirror image of each half. This line doesn't provide such.
The second image shows a parallelogram transverse by a dotted line that divides the figure in two equal areas, but again, this is NOT a line of symmetry because through the line, the half on one side does NOT reflect the other half.
If we fold the image through that line, both halves won't match exactly.