Adding image in proper Size in blogger post -

Step 1. go to dashboard -- theme---customise--- Advanced --- Add CSS - paste following code --

.post-body img {

max-width: 100%;

max-height: auto;

display: block;

margin: auto; 

}

Save by Clicking " apply to blog"

 Step 2 . Always select " original size " after uploading the image on blogger .

Done .

Ambadnya.