I suggest you use a time-based or flag-based way to select a new sprite image.
If you create a new robot or something, you need to draw him at least 3 times (1. left foot first, 2. both feet, 3. right foot first).
Load those images in darkbasic, for example nr 51,52 and 53
then use this to move him:
if rightkey()=1
inc move_image
if move_image > 53 then move_image = 51
else
move_image = 52
endif
sprite robot_number, x, y, move_image
this is just a basic way to achieve movement. Most coders (think about capcom: Megaman 1 > x3, etc) use more then 80 images for their main character. (jumping, shooting, walking, sliding, running, etc)
take a look at this site, and you'll see
http://www.angelfire.com/mn2/ryuujin/viewalls.html