Accessing a block types content programatically
This is a cutdown version of the function to access the block entities.

function _access_content_block_fields_build_arr($bidArr, $fieldRequestArr)
{

    $return = array();
    $blockElements = array();
    $blocks = \Drupal\block_content\Entity\BlockContent::loadMultiple($bidArr);
    foreach ($blocks as $block) {
        foreach ($fieldRequestArr as $fieldRequest) {
            $blockResult = $block-&gt;get($fieldRequest)-&gt;getValue();
            $blockElements[$fieldRequest] = $blockResult[0]; 
        }
        $return[] = $blockElements;
    }

    return $return;
}


purencool.com/accessing-a-block-types-content-programatically is the entire function for image fields url as well