Run the attached file in order to reproduce the problem.
In web:
In pdf:
Set up to reproduce:
<telerik:RadToggleButton ID="RadToggleButton1" runat="server" Text="RadToggleButton">
<ConfirmSettings ConfirmText="Sure?" />
<ToggleStates>
<telerik:ButtonToggleState Text="state1">
<Icon Url="supervisorIcon.png" />
</telerik:ButtonToggleState>
<telerik:ButtonToggleState Text="state2">
<Icon Url="ownerIcon.jfif" />
</telerik:ButtonToggleState>
</ToggleStates>
</telerik:RadToggleButton>