You also say:
1) Is there a way to restrict the gif animation to only show when the form has gone through?
Which is a bit different from:
2) when form is submitting.
I'm concerned now because the first request suggests you want the animation to play AFTER the form has been submitted while the second request suggests you want the animation to play WHILE the form is submitting.
The solution I provided will only work AFTER the form has been submitted successfully.