Check your img css.
Globally, img css may have a border definition which will render all images in your site that doesn’t declare a specific class or id to it. And if your stylesheet doesn’t address the hyperlink issue with images, then the parent CSS (ie: img) will take control.
img {
padding: 4px;
margin: 0;
border:1px solid white;
}
This will render all images with a white border, even images inside hyperlinks unless otherwise declared.
a img {border: none;}
This will render all images inside hyperlinks without a white border.
You can create a different class and leave everything else the way it is.
noborder-img {
border:none;
}
<a href="#"><img src="image link here height="10" width="10" class="noborder-img" /></a>
– [code adjusted by spencerp]