How to Increase Thumbnail Resolution /Size on Blogger

 When we add a widget on Blogger, the thumbnails will keep a default size of 72 x 72px which might not look good if we try to make them bigger using only CSS. However, with a bit of JavaScript we'll be able to replace the thumbnail with the same image of higher resolution and this way, larger images will no longer appear blurry.

In this tutorial we will see how we can replace the default thumbnail size of the popular posts widget but we can apply this trick on any of the blog widgets.

.

Changing the Thumbnail Size for the Popular Posts Widget

Step 1. First, let's add the Popular posts gadget by going to Layout > click on the Add a gadget link and select Popular Posts from the popup window.

Step 2. Go to Template > click on the Edit HTML button > click anywhere inside the code area and press CTRL + F keys to open the Blogger search box. Step 3. Type or paste the </head> tag inside the search box then hit Enter to find it. After you found the </head> tag, add this CSS above it:

<style type='text/css'>
.PopularPosts .item-thumbnail a {
clip: auto;
display: block;
height: 130px;
margin: 0 0px 5px;
overflow: hidden;
width: 210px;
border: 2px solid #EEEEEE;
border-radius: 20px;
}
.PopularPosts .item-thumbnail img {
position: relative;
top: -30px;
transition:all .2s linear;
 -o-transition:all .5s linear;
-moz-transition:all .2s linear;
-webkit-transition:all .2s linear;
}
.PopularPosts .item-thumbnail img:hover{
opacity:.6;
filter:alpha(opacity=60)
}
.PopularPosts .widget-content ul li {
background: #F9F9F9;
border: 2px solid #EEEEEE;
border-radius: 10px;
box-shadow: 0 4px 10px #EEEEEE;
color: #555555;
padding: 10px;
margin-bottom: 5px;
}
.PopularPosts .item-title {
font: 14px Cambria,Georgia, sans-serif;
color: #2288BB;
font-weight: bold;
text-transform: uppercase;
text-align: center;
}
.PopularPosts .item-snippet {
display: none;
}
.widget .widget-item-control a img {
height: 18px;
width: 18px;
}
</style>

Step 4. Search for the </body> tag and just above it, add this script:

<script type='text/javascript'>                  
function changeThumbSize(id,size){
var blogGadget = document.getElementById(id);
var replacement = blogGadget.innerHTML;
blogGadget.innerHTML = replacement.replace(/s72-c/g,"s"+size+"-c");
var thumbnails = blogGadget.getElementsByTagName("img");
for(var i=0;i&lt;thumbnails.length;i++){
thumbnails[i].width = size;
thumbnails[i].height = size;
}
}
changeThumbSize("PopularPosts1",210);                  
</script>

What I highlighted in red is the widget ID for the Popular Posts gadget - to change the thumbnails size for any of your blog widgets, first you need to find the gadget/widge ID and then add a line below this part:

changeThumbSize("PopularPosts1",210);
changeThumbSize("widget-ID-HERE",210);

 ... and replace widget-ID-HERE text with the ID of that widget/gadget.

Note: you'll not be able to see the changes if the widget has a class selector - for this you will need to change class with id and replace the dot "." symbol with "#" within the CSS...

Step 5. Finally, Save the Template. 

If you need more help, please leave a comment below.