/* for low resolution display */
img.CC-BY-NC-ND-88-31 {
    background-image: url(../../imagens/CC-BY-NC-ND);
    background-repeat: no-repeat;
    background-size: px 31px;
}
/* for high resolution display */
@media only screen and (min--moz-device-pixel-ratio: 1.5),
only screen and (-o-min-device-pixel-ratio: 3/2),
only screen and (-webkit-min-device-pixel-ratio: 1.5),
only screen and (min-device-pixel-ratio: 1.5) {
img.CC-BY-NC-ND-88-31 {
    background-image: url(../../imagens/CC-BY-NC-ND@2x);
    background-repeat: no-repeat;
    background-size: 88px 31px;
}
}