I’ve also created a button and fill it with a gif, but I can’t reproduce the same issue as yours, I can normally view it in the Power BI service.
In desktop:
In service:
Therefore, I suggest you to update to the latest version of the Power BI desktop and publish the report again to overwrite the original report in the Power BI service to check if this problem can disappear.
In button, it is filled with normal png but hover effect is gif. That isnt working. My power bi desktop is the latest version and republishing didnt help.
We're electing to do a code fix to mitigate this and make sure it works on all user agents and whether GPU utilization is turned on in the user agent. This fix will ride the 10.1 train, which will be deployed Oct 4-6 to PROD. No workaround in the meantime, unless a different visual is used.