Congrats mate but Radha Never Married Krishna so pic seems irrelevant if i am not wrong . But if that is Rukmani with Krishna then that is excellent choice of PIC .
Radha and Krishna are the depictions of a pure relation... While Rukmini is a relation that can be considered as a lucky one, because others can't relate to Krishna in a physical way -- like you are not related to Krishna the Lord, or I'm not any way connected to Lord in a physical way -- for example, I cannot be called His great grand nephew or likewise.
Radha makes it possible for me to still connect to Him eternally, as is the fact which the
Maya (Google it) makes me forget it from time to time.
The means of being like Radha lets me bridge that connection to Lord Krishna. Being like Radha means I can still love Him as much (as she did), and then a very pure relations takes form, and it connects me, a part, with the One who is the Whole. It depicts the relation I always had and will have with my Lord, and that too without any limitations (such has being "related" to Him in an Earthly way). So in a marriage too, the Radha Krishna couple is symbolic to depict the real union or connection that lies between a wife and a husband.
Hindu mythology tells that the marriage is a bond that exists over many lives. The bond is an eternal one, though time has twisted the real meaning, and it fulfills the meaning of creation of the universe... the show must go on, and for it to go on it needs at least a couple!
The connection between the couple that exists from the beginning and will last till the end is the Radha Krishna spiritual connection... then they will cease to look like they are two different entities and will merge together, as they always were (never were two entities ever. That's the
Maya or illusion for you).
So, is the deep spiritual and physical meaning on a marriage card... The
eternal love that's not bound to any earthly mean, but only which that makes possible the physical eternal and pure union till death and beyond!
Radhe-Krishna means I and He are two forms that never were different. The form gives me a means to love my dear Lord which He too loves as much. The two different forms are made by the Lord Himself to play a grand game of life, and to have someone created out of Himself to feel an eternal and unlimited Love for Himself. It's is a form that keeps Him delighted and ever-joyed as He plays this wonderful game of Life all by Himself!
Radha depicts the pure spiritual love and connect of Hindus towards Lord Krisha, it also depicts the pure spiritual love Christians have towards Lord Jesus, and so on. It though seems to depict physical love is in fact related to the purity of the spiritual love that connects us with Him eternally... So it's actually the spiritual connection between souls, and between us and Him, while
Rukmini also is depiction of the same spiritual connection but with a predominant physical sense of the same Love. Radha is the eternal-ness of our relation with the One Creator.
For those who don't beieve in God, this form (Radha) is the connection between us and the Power that powers all the universes. It's the power that keeps us going eternally...