Just a few guesses:
If you use the select box to edit but don't click on the edit screen to set that box it will not save the edit and will revert back to image before edited.
If you accidentally click a apply to whole animation or apply to all animations while in paste mode or changing the size or setting the collisions that will apply to all animations in a frame and all animations in the entire sprite.
You won't see that happened until you close the sprite and play it or go back and look at the sprite again and if you save it that is why you would see sprites not as you wanted them.
I noticed in the first pic you do not have the sprite cropped and if you do not crop and then set that sprite to a specific size in your events it may appear blurry or stretched.
Good idea to crop each image as you edit.