Hello,
I am using Sparkling theme.
On my blog posts page, I would like the thumbnail to appear as a small, squared picture on the left of post title and text, instead of large and above. (like it is on the attached photo)
Thank you for your help.
Hi there
Hope you are having a good day and thank you for your question 
To reduce the size of the image thumbnail, you would need to customize the theme’s template file. Unfortunately, this is not something we can assist with from our end.
Thanks!
Colorlib Support Team