Images of the reclining Buddha are fairly common, they can both be images of the Buddha sleeping or reaching his Parinirvana (Sutra Mahayana of Mahaparinirvana) before to leave his physical body.
In the Thai tradition, the reclining Buddha is called Phra Nön and Phra Sayiasna.
It is the protector of people born on a tuesday and its color is pink.
Parinirvana of the Buddha (Photo credit : Wikipedia).
To know if an image of the reclining Buddha depict his death or merely his sleep,
one has to look at...his feets position.
The reclining Buddha of Wat Pho (Picture credit : Terry Kelleher).