.bg-login-image {
    background: url("https://plataforma.pcbem.pt/assets/uploads/store_0/ac0301a54d3bcf0ad1ad39cb94b3d8f5b62cf409_f4a933cbdb3b800b8bb6476ebe397bb4_f45a810e3be1d9411af42ed8ab2a785f85ee3665.jpg");
    background-position: center;
    background-size: cover
}

.bg-register-image {
    background: url("https://plataforma.pcbem.pt/assets/uploads/store_0/ac0301a54d3bcf0ad1ad39cb94b3d8f5b62cf409_f4a933cbdb3b800b8bb6476ebe397bb4_f45a810e3be1d9411af42ed8ab2a785f85ee3665.jpg");
    background-position: center;
    background-size: cover
}

.bg-password-image {
    background: url("https://plataforma.pcbem.pt/assets/uploads/store_0/ac0301a54d3bcf0ad1ad39cb94b3d8f5b62cf409_f4a933cbdb3b800b8bb6476ebe397bb4_f45a810e3be1d9411af42ed8ab2a785f85ee3665.jpg");
    background-position: center;
    background-size: cover
}
<div style="border:1px solid #990000;padding-left:20px;margin:0 0 10px 0;">

<h4>A PHP Error was encountered</h4>

<p>Severity: Warning</p>
<p>Message:  Cannot modify header information - headers already sent by (output started at /home2/pcbem/plataforma/system/core/Output.php:538)</p>
<p>Filename: core/Common.php</p>
<p>Line Number: 570</p>


	<p>Backtrace:</p>
	
		
	
		
	
		
	
		
	
		
	
		
	
		
	

</div>
<div style="border:1px solid #990000;padding-left:20px;margin:0 0 10px 0;">

<h4>A PHP Error was encountered</h4>

<p>Severity: Compile Error</p>
<p>Message:  Declaration of Phalcon\Translate\Adapter\AbstractAdapter::offsetUnset() must be compatible with ArrayAccess::offsetUnset($offset)</p>
<p>Filename: Unknown</p>
<p>Line Number: 0</p>


	<p>Backtrace:</p>
	
		
	
		
	
		
	
		
	

</div>