When designing the preview, mockups of the following authors were used:  

<a href='https://ru.freepik.com/psd/background'>Background PSD создан(а) rawpixel.com - ru.freepik.com</a>

<a href='https://ru.freepik.com/psd/background'>Background PSD создан(а) lucecitavectors - ru.freepik.com</a>

<a href='https://ru.freepik.com/psd/frame'>Frame PSD создан(а) lcd2020 - ru.freepik.com</a>