Ok, if you have different image points on different sprites, then my second advice about loading images from files will not work.
But you still need some way to store all this data about each sprite, their animations and images in each frame.
How else would your game know that frame10/sprite1 and frame9/sprite2 is the same image?
You need to put this information into an array first and then check this array when picking a random frame.
You can try Extract image plugin, maybe it will allow to compare two images. Keep in mind though that the images should be 100% identical, even a difference in 1 pixel will produce a different string.
The only other idea that comes to mind is to use image points to store image number.
Say, in frame10/sprite1 you create an image point named "ImageNumber61", in another frame "ImageNumber23" etc.
Then you can use a rather complicated method to determine what image point name "ImageNumberX" is defined in each particular frame. But this is a bad idea and I don't recommend it. Use an array instead.