How to set background image for section
Go to the specific section where you want to add a background image. Click the Image icon in the section settings, and go to the image tab then set the background image.
Once the background image has been inserted to the section, adjust or set the opacity, background repeat, background position and size right below the background image tab.
Click the Overlay tab to set an overlay color over the background image. You can choose either to set a background color overlay, linear gradient or radial gradient.
NOTE about image sizes:
If your image looks grainy or blurry, you'll want to make sure you selected the full size version of the image. The default behavior of WordPress when you upload files will be to offer the file in various file sizes depending on settings in your WordPress Theme, or WordPress default behavior.
If you previously selected a smaller size for an image somewhere else on your site, and you then add an image with OptimizePress, WordPress will remember your setting and automatically select the smaller size option. You'll then want to make sure you change this to the proper size, or full size image depending on what you need for where you are adding the image.
We use the default media library options built into WordPress in order to ensure ongoing compatibility and ease of use, so these options are not coming directly from OptimizePress which is why it works this way.
You may select the image size you want after you select the image you want to add, as you can see in the following screenshot: