If you want to load an image in the sidebar, you can’t upload it the same way as if you are putting it in the content column using Blogger upload facility. You will first have to host the photo on the web, perhaps using the popular photobucket and get the url for the photo. Alternatively you can use a workaround to get Blogger to host for you.
If you do, first, post an empty post with the photo uploaded in the normal way. You may click on the photo to highlight it, then click on the corner and drag it to the size you want in the COMPOSE mode (wysiwyg window).
Open the post, and click on the photo. You will be taken to a page with only the photo. As an example, I will upload an image in this post. If you click on the image (try it) you will see that the url of the image is. Copy the url of the (your) photo. Click the TEMPLATE tab to open the template editor. Then in the sidebar, where you want the photo, type in this code:
<p><img src="http://photos1.blogger.com/bl....2.jpg" alt="photo title" /></p>.
<!-- Begin #sidebar -->
<div id="sidebar"><div id="sidebar2">
<!-- Begin #profile-container -->
<$BlogMemberProfile$>
<!-- End #profile -->