Vertical Mirror Matrix

You are given a 2D matrix of integers with dimensions m x n. Write a function that finds the largest contiguous submatrix that is symmetric along its vertical axis. A submatrix is considered vertically symmetric if, for every row in the submatrix, the elements read the same from left to right as they do from right to left.

Your function should:

• Identify the coordinates of the top-left and bottom-right corners of this submatrix.
• Return the dimensions (number of rows and columns) of the submatrix.
• If multiple submatrices of the same maximum size exist, it is acceptable to return any one of them.
• If no such submatrix exists, return an appropriate indication.

Consider the following when designing your solution:

• Think about how you can efficiently verify the vertical symmetry of any given submatrix.
• Your approach should be optimized for scenarios where m and n could be as large as 1000.

Example:

Given the matrix:

[1, 2, 2, 1]
[3, 4, 4, 3]
[5, 6, 7, 8]

One acceptable result is identifying the submatrix formed by the first two rows (which is vertically symmetric), along with its coordinates and dimensions.

Implement your solution in the programming language of your choice.