change anonymous avatar in blogger comments

I am having issues with changing the default avatar used in native Blogger/Blogspot comments for Anon + Name/Url users.

I have tried this:

.avatar-image-container svg { 
  width: 35px; 
  height: 35px; 
  background-image: url(some-uploaded-photo.jpg); 
  background-size: contain; 
  color: transparent; 
} 
.avatar-image-container svg use { 
  display:none; 
}

This:

<script> var oldSrc = '//img1.blogblog.com/img/blank.gif'; //Default blogger image link
var newSrc = 'https://3.bp.blogspot.com/-UNjtW9_9fcs/VrvrBJi_8CI/AAAAAAAABP4/jjFMkoCi6Ig/s1600/blank-user-avatar.png'; //New image link
$('img[src="' + oldSrc + '"]').attr('src', newSrc); </script>

This:

<script src='http://code.jquery.com/jquery-latest.js'/>
<script>
$(&quot;img[src=&#39;http://img1.blogblog.com/img/anon36.png&#39;]&quot;)
.attr(&#39;src&#39;, &#39;http://1.bp.blogspot.com/-Zphr2YJH_6w/T6ZZE4YeNBI/AAAAAAAACF0/Tyuj8hkOpdc/s1600/default_avatar.gif&#39;)
.ssyby(&#39;blank&#39;)
</script>
<script src='http://code.jquery.com/jquery-latest.js'/>
<script>
$(&quot;img[src=&#39;http://img2.blogblog.com/img/b36-rounded.png&#39;]&quot;)
.attr(&#39;src&#39;, &#39;http://1.bp.blogspot.com/-eKbzORzVaBQ/T6ZXHmdgHqI/AAAAAAAACFs/rVy3T4gxojM/s1600/blogger-user.png&#39;)
.ssyby(&#39;blank&#39;)
</script>

And this, which is very similar to the first above:

.avatar-image-container {
background: url(http://1.bp.blogspot.com/_7wsQzULWIwo/SxL-DRXzmWI/AAAAAAAACY0/d1g3ymxGLEQ/s400/avatar.gif);
width: 36px;
height: 36px;
border-radius: 50px;
border: 1px solid #fff;
}

The closest I get to a result is this last code (it does show the avatar used here) until I add the URL link to my own image. I have tried editing the HTML direct and adding as CSS and tried hosting it on Blogger + externally in both JPG and GIF formats to no avail.

Any ideas? Please? This is really weird and driving me a little nutty.

Thank you!

:: blog that this relates to is >> https://guplayground.blogspot.com/ <<

// resolved //

Use an image (jpg/png) that is 36px x 36px! Anything larger will not resize to fit

;)