You resized the preview in a way that is not considered pixel art. You must crop or manually resize the original image or create a new image for the preview.
Techniques do not understand what you mean. That was my first animation in pixel art and maybe does not export very well: P I apologize
Also, you're preview looks like it was resized using NPA techniques.
Nice, but you're going to want to make the background transparent instead of white, just a PJ rule.
Also, welcome!! ^^
sending this back for the background and preview. feel free to resubmit (under EDIT IT options) once these changes have been made.