Go here (replace with your own individual edit site link): https://REPLACE-SITE-URL-HERE.squarespace.com/config/design/site-styles/colors
Each section of your site has the name of the theme being used on the top right (highlighted with red border below, in my case it's "Lightest 2")
On the Colors side panel, find the theme where you want to remove the image overlay from. Click on the Edit button.
The side panel updates to an "Edit Theme" panel, where you can scroll down to about 2/3rds where you start seeing "Image Block" sections. Find the image block you are using for your image, and click on the Image Overlay item.
That opens a couple of new options, but you are going to move the gradient circle in the bar all the way to the left.
->
Now save your changes by clicking the Done button on the top left.. and you're done!
