>I want to pass the content of memo (that is actualy a picture file) to a temporary file, how can I know the type (bmp, jpg, ...).

This will do for most common graphics formats:

FUNCTION ImageTypeAutoDetect
LPARAMETERS m.ImageFile

DO CASE
CASE LEFT(m.ImageFile,2) == "BM"
  m.lcType = "bmp"
CASE INLIST(LEFT(m.ImageFile,6),"GIF87a","GIF89a")
  m.lcType = "gif"
CASE LEFT(m.ImageFile,2) == CHR(0xFF) + CHR(0xD8)
  m.lcType = "jpg"
CASE INLIST(LEFT(m.ImageFile,3),"II*","MM*")
  m.lcType = "tif"
CASE LEFT(m.ImageFile,8) == CHR(137) + "PNG" + CHR(13) + CHR(10) + CHR(26) + CHR(10)
  m.lcType = "png"
OTHERWISE
  m.lcType = ""
ENDCASE

RETURN m.lcType