does it have a theme?
It shows a scene from the biblical entombment of Christ.
The Entombment (Bouts)
 It shows a scene from the biblical entombment of Christ, and was probably completed between 1440 and 1455 as a wing panel for a large hinged polyptych altarpiece. 
what is the entombment? It is a glue-size painting on linen. who is the painter? Dieric Bouts.
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The Entombment (Bouts) [SEP] Introduction
The Entombment is a glue-size painting on linen attributed to the Early Netherlandish painter Dieric Bouts. It shows a scene from the biblical entombment of Christ, and was probably completed between 1440 and 1455 as a wing panel for a large hinged polyptych altarpiece. The now-lost altarpiece is thought to have contained a central crucifixion scene flanked by four wing panel works half its height – two on either side – depicting scenes from the life of Christ. The smaller panels would have been paired in a format similar to Bouts's 1464–1468 "Altarpiece of the Holy Sacrament". The larger work was probably commissioned for export to Italy, possibly to a Venetian patron whose identity is lost.