Is this an image?

imagep expression
image? expression

Returns true if expression returns an image.

Example:

repeat 9 [fd 70 rt 160]
make "img image {-40 -10} {50 80}
stampat {150 0} :img

print image? :img
print :img

print image? turtleimg
print turtleimg

Output:

True
bitmap90x90
True
bitmap27x27

See also:

Type predicates