streaming images unicast

I never used vlc or ffmpeg or any other kind related software so i'm really newbie in this stuff.

I need to mount a "system" to streaming pictures, i thought maybe i can make a video and stream it, but with this process i lose flexibility to change on-the-fly pictures since i need to "encoding" (not sure if right word) the pictures in video and stream the video (other problem is like the refresh time of the pictures are different making a video leaves me a problem, i cant have a video larger that the minimum re开发者_如何学JAVAfresh rate or the rest of the video will never be show....).

what i would like is to stream a group pictures in a loop where i could change the pictures on-the-fly with no problems... don't know if that is possible..

ffmpeg -loop_input -r 0.5 -i %1d.jpg -vcodec mpeg4 - f mpegts udp:IP:PORT

this streams a video of those images, but when i change them or add new ones the output is not update.