Automatic Thumbnail and Read More Function for Blogger | Template Doctor

Follow steps:
1. Go to "Design" click "Edit HTML"
2. Tick on "Expand Widget Templates"
3. Find this code

<data:post.body/>

4. Replace with this code below

<b:if cond='data:blog.pageType == &quot;static_page&quot;'><br/>
<data:post.body/>
<b:else/>

<b:if cond='data:blog.pageType != "item"'>

<div expr:id='"summary" + data:post.id'><data:post.body/></div>
<script type='text/javascript'>createSummaryAndThumb("summary<data:post.id/>");
</script> <span class='rmlink' style='float:right;padding-top:20px;'><a expr:href='data:post.url'>read more</a></span>

</b:if>
<b:if cond='data:blog.pageType == "item"'><data:post.body/></b:if>
</b:if>

5. Now, search for </head> and paste the following section of code immediately before it:

<script type='text/javascript'>var thumbnail_mode = "no-float" ;
summary_noimg = 430;
summary_img = 340;
img_thumb_height = 100;
img_thumb_width = 120;
</script>
<script type='text/javascript'>
//<![CDATA[
function removeHtmlTag(strx,chop){
if(strx.indexOf("<")!=-1)
{
var s = strx.split("<");
for(var i=0;i<s.length;i++){
if(s[i].indexOf(">")!=-1){
s[i] = s[i].substring(s[i].indexOf(">")+1,s[i].length);
}
}
strx = s.join("");
}
chop = (chop < strx.length-1) ? chop : strx.length-2;
while(strx.charAt(chop-1)!=' ' && strx.indexOf(' ',chop)!=-1) chop++;
strx = strx.substring(0,chop-1);
return strx+'...';
}

function createSummaryAndThumb(pID){
var div = document.getElementById(pID);
var imgtag = "";
var img = div.getElementsByTagName("img");
var summ = summary_noimg;
if(img.length>=1) {
imgtag = '<span style="float:left; padding:0px 10px 5px 0px;"><img src="'+img[0].src+'" width="'+img_thumb_width+'px" height="'+img_thumb_height+'px"/></span>';
summ = summary_img;
}

var summary = imgtag + '<div>' + removeHtmlTag(div.innerHTML,summ) + '</div>';
div.innerHTML = summary;
}


//]]>
</script>

clarification code above:

summary_noimg = 430; is post cut height without image
summary_img = 340; is post cut height with image
img_thumb_height = 100; is thumbnail image height
img_thumb_width = 120; is thumbnail image width