How to harmonize my animations?

I have a problem: I've almost set up my first scene with one character. Due to the visionaire tutorials in youtube, I've created all the different aniamtions for this character. But now, when I run the game, I recognize that the different animation sequences aren't exactly the same size. Because of this, f.e., if my character first stands and then goes, it gets a bit bigger when it moves and that looks a bit strange. So I wanted to get this problem fixed with the eye tool (harmonize with other character animations). But I don't get this tool. Though you can choose two different animations, you can't harmonize the sizes.. I don't get in which way this tool is necessary then. Or have I just overlooked how it works???

I really hope that someone can help me, because the only possibility I know is to change the size in my graphics program but this would take to much time...
Thank you.

the harmonize tool is more of a re-alignment purpose than anything else for making sure your animations transition smoothly between each one by aligning them correctly & giving each the same animation center.

much simpler solution for character animation is to create all your character animations inside of a bounding box (if you're doing frame by frame) in layers & even better yet with one of your games backgrounds behind or a placeholder so you can see what the character will look like on the scene... the bounding box is also useful for keeping character proportions correct etc as you can create ruler lines or use a semi-transparent character image behind for reference.

if all the frames for each individual character have the same background width & height then you don't need to bother messing about with harmonize.