How to resize your survey icons
Currently, this cannot be completed from within your Thermometer Builder. Therefore, you'll need to save the icons to your desktop and resize them using image editing software such as Photopea which is free. Once resized you can re-upload them using the 'Add custom icons' tool in your Thermometer Builder.
Don;t forget to hit 'Give me my Thermometer' to generate your survey to then produce your new survey.