Hi perezbalen,
I'm not sure if you have seen this manual entry...
scirra.com/manual/48/image-and-animations-editor
but it might have the answers you want. You can have mant different anims for a sprite. When editing in the image editor, an animations box pops up, you right click in there to add an animation. When you click on the anims in that promt box you can edit each anims frames individually. The first prompt to add a sprite allows you to only add one frame, but once that sprite is added you can right click in the frames editor and import a bunch at one time. I keep all frames for each anim in a single file folder, so they are easier to dump into the image editor. Not sure if any of this is a help to you. Check out a few more tutes, I think its covered here and there...good luck!