You can upload animated GIF images to your Merchant Solutions store. However, if the store software resizes your image to fit, only the first frame of your animation will be captured and displayed in the resized image.
It is not possible to animate buttons in your store. If you upload an animated GIF to one of the button image related properties, only the first frame of the animation will be captured and used for your custom button image.
You can upload files to your Files area, then use HTML to reference a specific image file.
Note: Images for upload can't exceed 2 MB in size, 2 million pixels in total, or 1400 pixels in width or height. Images that exceed any of these maximum values won't upload.