Hi Moustafa, I think you can try the Photoshop or Imageready, which are famous and often used in figures's preparation. These softwares can directily recognize the .png file without format convertation. And the movie can be easily made. Every .png file can be introduced as a layer and the show interval can be freely designed. Finally the movie can be saved as .gif format, which can be directly used in MS ppt.
Good luck! Ning ¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡ ¡¡¡¡ ¡¡2007-05-27 ---------------------------------- Ning Shen, Ph.D. graduate Institute of Biochemistry and Cell Biology Shanghai Institutes for Biological Sciences Chinese Academy of Sciences 320 Yue-Yang Road Shanghai 20031 P.R. China Tel: 021-5492-1217 Fax: 021-5492-1116 Email: [EMAIL PROTECTED]