So, what is the difference between your sprites if they all have the same behaviour?
Basically, the atributes...
Imagine my example: the "Monster" object have events for losing hp, destroy the object when hp <= 0, walk, run, flee, attack, etc.
All those elements should be the same for all monsters, considering it's speed, size, hp, strenght, image/animations, etc etc. You see?
The "solution" so far that i tought is to have a monster object, with all monsters i have on single frames and an array containing it's default attributes, indexed by monsters image frame.
So on frame 1 have a turtle? on arrayMonstersInfo i have turtle's data;
On frame 2 a dragon? arrayMonstersInfo contains dragon's data, etc etc.
The problem here would be only the animations =/