How to prevent your blog logo thumbnail from showing any time you share your post to social media
For short, go to the page and . click on edit and add a featured image for your page . Social media sites try to fetch the featured image for your page first. if they dont find featured image then they look for any other image present on website. I think you dont have any featured image for your page or either you have placed your logo in the featured image. Change it and you are done .
Alternate method :
If you use yoast seo plugin , then their is an option to customize how you want your link to look when shared on social media. Thats a much easy way i guess.
Open your page in edit mode -> Go below and find Yoast seo snippet -> In the left Sidebar you can see some options to choose . CLick on Share button .
Here you can now customize how your link looks like when shared on social media
hope it helps