The painting most probably comes from Byzantine Tradition as we can see the image of the Father is the one sitting on the Throne and Jesus the Begotten Son is not yet a grown up man nor presented as the Glorified One having His own throne as King of Kings. The Holy Spirit also is represented after the image of Jesus. The artist presented the Holy Trinity in heirarchical fashion.
The painting title can be expressed as " The Abba Father Divine Plan of Salvation" by sending His Begotten Son and by Jesus holding the Holy Spirit meaning He has the power in sending the Holy Spirit depicted in the symbol of a dove.
Further deciphering the image we can describe them as follows;
The Abba Father wears a white garment signifying holiness, his right hand raise in a familiar hand symbol of Jesus having the 2 fingers, others interpret this as 2,000 years. The left hand of the Abba Father is holding a white paper can be interpreted as the Abba Father's written Divine Plan for Mankind Salvation. Abba Father halo is represented by a lot of triangle formation representing the Wisdom of the Holy Trinity.
Jesus the Begotten Son is clothe in gold representing purity as Jesus will come in the form of man devoid of Majesty and Glory but will be born sinless or pure. Jesus halo represented the symbol of Cross signifying His Redemptive mission was already foreordained in Eternity before He came into this world.The "Way of the Cross"(Genesis1:1)
The Holy Spirit was represented by a dove like when it came down to Jesus to dwell with Him in the Baptism in the river Jordan. The halo of the dove is represented with two colors blue and white. The blue & white color is the color of garments of Our Lady as the Holy Spirit unlike Jesus will not be incarnated but instead will indwelt mankind. Mankind will be the Temple of the Holy Spirit. The Holy Spirit perfectly dwells in Mary as St.Kolbe called it "quasi-incarnate" can be found in Proverbs9:1
The left and right image of the sun signifies that the Holy Trinity is the source of Light or sorrounded by Light. They are enclosed in concentric circles meaning it is in their own volition that the Divine Plan was conceived. The Divine Plan excluded the angelic realm as some had been teaching that angels participate in the Divine Plan.
In closing, the artist did not presented the Most Holy Trinity as co-equal but rather shown the Abba Father has the Highest Authority having the one seated at the Throne. This is not to tell that they are not co-equal but rather the artist depicted their individual role in the Divine Plan as drawn out by the Abba Father represented by a white paper in His left hand. And the right hand symbolizing only the Abba Father knows the hour of completion of His Divine Plan. The Holy Trinity equality is shown in the Head of the Abba Father represented by triangle symbol meaning their Wisdom are co-equal but differs in each individual role to play.