is it possible to have an preview of pictures on my desktop? How?
You may want to look at xfdesktop which can display one picture at the time. Type xfhelp4 at a command prompt to see the documentation of all xfce4. Alternatively you could use another program to manage a collection of pictures as wallpaper -- I have used a shell script, but you can also use chbg (dated but very functional).
i probably expressed my self the wrong way.
i don't want to have pictures grabbing my desktop but the thumbnail of pictures saved on desktop (in folder ~/Desktop) just like picturepriview while using filemanager.