Code-Snippets-Functions/Execute a function on a child site/ShortPixel Image Optimizer/skip-backup-main-image-only.txt

function sp_filter_thumbnails($result, $fullPath, $isMainFile ) {
        $result = true;
        if ($isMainFile) {
                $result = false;
        }
        return $result;
}
add_filter( 'shortpixel/image/skip_backup', 'sp_filter_thumbnails', 10, 3 );