When I try to resize a gif in Confluence, the image comportment is not correct :

• when I resize with the editor UI, if the image is too small, the gif is not animated.
• when I resize it with a HTML macro and a img element defined with a width attribute, there is no issues, the image is correctly resized and animated.

I tried this with Firefox 41.0.2 and Chrome 46.

Workaround

To resize the image and retain the animation, use the HTML macro and define a new width in the <img> tag