You can currently use images in the DataFormEditorStyle's PositiveFeedbackImage
(see here for tutorial
I see that you don't currently have a trial or dev license yet. If you download the trial, you'll also get the full example application (it will be at the following location after installation: C:\Program Files (x86)\Telerik\UI for Xamarin R1 2017\Examples\XamarinForms
You can also create a Custom Editor for your exact needs, see here
for how to get started.
Lance | Tech Support Engineer, Sr.
Telerik by Progress
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