WordPress auto-editing code

This is the most annoying thing about WordPress.

WordPress would sometimes auto-edit your code or whatever it is it does, its really annoying.

For example, I would push enter twice to allow space between the pictures. But once I save it, that space is gone.
I’ve tried entering <br> and <p> tags but they just get erased once saved.

How do I fix this problem? It is extremely annoying