After googling a lot and searching in the forum, I can’t find a simple solution to project pictures from a lamp within cycles.
I assume spherical projetion or parallel/sun projecion is related to the type of lamp.

Actualy the color in preview slot of “lamp” object changes, but I can’t read any pictures.
I’ve tried with a png and with a procedural pictures, with different mapping/scale parameters.

PLEASE DO NOT!!! use a PDF for a simple jpg image!!!

sorry for that !
I’ve found a more complete tutorial from gleb alexandrov here:

and it let me to play with parameters a lot better: