'mFrame' being max count of frames.
Local variable 'OnScreen'
Top level event : is on screen
action ... set variable OnScreen to Sprite.pickedcount
Sub event : Same event: System > For "i" = 0 to mFrame
sub event : Sprite > Compare frame > frame = loopindex("i")
In same event : System > compare 2 values .. 1st 'OnScreen' ... = .. 2nd Sprite.pickedcount
action > stop loop
action > whatever you like, because if this condition is true, they all have the same animation frame, set a local variable or so
The other
Local variable 'OnScreen'
Top level event : is on screen
action ... set variable OnScreen to Sprite.pickedcount
sub event : sprite animation frame > 0
sub event : system compare 2 values ... 1st OnScreen ... = .. 2nd Sprite.pickedcount
action ... when this actions run, there is no sprite on screen with frame = zero