..yes, its still one of the most commonly asked questions..
.."How do I remove borders of my pictures in Blogger.com?".
Well the answer is simple.
Go to your Blogger template, select advance view and "Add CSS",
.post-body img { border: none !important;
}
Note, all credits go to the fantastic guys behind helplogger blog.
You can find them here: helplogger - how-to-remove-blogger-pictureimage
There you go, simple! :)