If you've uploaded an animated GIF into the assets library then added it to the page using the WYSWYG then yes you will likely find that the animation no longer works - because the image is processed/resized by Voice.

However, there is a trick that lets you use the original image as-is on the page, so that it will animate correctly.

1. Click the Insert/edit image button as usual to bring up the image adding dialogue and, as usual, click the button to the right of the Source input to open the popup to select the image. However, before you click Save to add it to the page... 
2. In the Source input field, add ?attr=image_orig to the end of the asset's URL. For example, if it was:
   /yoursitename/assets/images/mypicture
   then you should change it to:
   /yoursitename/assets/images/mypicture?attr=image_orig
3. Now click the Save button to add it to the page.

You'll find that the image exactly as uploaded is now displayed. This works for all images in the Assets Library, not just animated GIFs, should you ever wish to put the image exactly as uploaded onto a page.

Thanks

Joe