Hello Milanesi,
Thank you for these questions.
If you need to change the color appearance of a single day, please refer to our Quick Start Framework application, section
RadCalendar >> ElementRender Event where we have an example of this scenario.
Regarding the image association, please refer to our Online Help Documentation article:
Using Templates.
If you have additional questions, feel free to contact me.
Best wishes,
Nikolay
the Telerik team
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