Hi, you can do this:
Have just 1 object for blood, but the 2 differentes sprites as frames in the animation... set the animation speed to 0.
then create that object (blood) and "set animtion frame" to choose(0,1) that will choose either frame 0 (blood 1) or frame 1 (blood 2) and that's all.
one more thing, it's easier when uploading files to save as capx.
good luck