Ionic tabs icons are jumping/flickering


I am new to ionic, in my project i am using ion-tabs.
In that i using custom images as tabs icons, there are two images for each tab i.e. one for icon-on and another for icon-off.
The issue is, while clicking on tab tab icon gets larger and again after few milliseconds it is in normal size i.e. on same position means it is jumping or flickering.
So I don’t want icons to be jump, it stays on its original fixed position.
please help me if any one have solution for the same.

Thanks In advance.