How do I get a thumbnail preview of an image at the side of the meta-description in SERP for mobile?

You need to add structured data and rich snippets on your website. Also, you have to optimize your web pages properly. Now, the search engine will crawl that automatically, your website gets a thumbnail preview of an image at the side of the meta-description in SERP for mobile and you don't need to do anything.

Search Engine Results Pages (SERPs) are constantly evolving. Google is getting better at understanding what people are searching for and determining what content satisfies that search.

But that isn’t the only way Google is changing the landscape of SERPs.

you have to optimize your web pages properly

You can search rich snippet for more infomation.

use macro data also known as schema markup within ur page/post to tell everything about your page/ post to search engine. This way Search Engine will get to know what is your page and they will display the image within the search result, image url you gave within macro data

You can view the Thumbnail image beside the meta-description by including an image alt tag into the schema markup.

Amod Nazirkar, You asked nice question.
you are watching Thumbnail Image besides the meta-description in search Engine Results that is from website "FAVICON".
You will have to install a favicon on your website.
Favicons are small square images usually 16×16 pixels which are used by web browsers to show a graphical representation of the site being visited at the left side of the browser's address bar.

you have to optimize your web pages properly

Optimize your website and web pages properly. Add Alt Tag attribute on your images and use your own images, Google automatically crawls images and show in google images. you don't need to do anything.

Thanks Guys !!!

So I reckoned that in order to get the Thumbnail Image in the SERP besides the Description in Mobile Resolution, that particular image which we want Google to display as a thumbnail should be present on the page of that SERP result URL. That Image should also have an Alt Tag preferably matching to the Search Query.

Any further Inputs ???

You need on page optimization your page

fully agree with @RonyNeogi
you have to optimize your web pages properly, also have to add alt tags in the images, the search engine will crawl that automatically, you don't need to do anything.

You need on page optimization your page

you need to advance your website pages appropriately.

you have to optimize your web pages properly

you have to optimize your web pages properly, also have to add atl tags in the images, the search engine will crawl that automatically, you don't need to do anything.

please, as i also want o know that How do I get a thumbnail preview of an image at the side of the meta-description in SERP for mobile?