, .
, Firefox, no-image img , width height CSS.
HTML-:
<img alt='no image' src='about:blank'><br>
<img alt='no image' src='about:blank'id=iblock>
CSS:
img {
height: 100px;
width: 100px;
background: cyan;
}
#iblock {
display: inline-block;
}
JsFiddle.