Can I stop Blogger from resizing my images?

[SMT]

It can be re-sized directly from HTML mode instead using long process, for that;

Go to post, insert any image in Compose mode
Switch to HTML and delete the height and width, then image code will look like this;

img border="0" src="http://4.bp.blogspot.com/-ThgNR-wIpqQ/UuYzw9qPRcI/AAAAAAAACiI/Vf6Uxi5VsD8/s1600/Koala.jpg" /></a></div>
<br /></div>

Change the s1600 to any desired number lets say s795
That's it. it will fix the size of image.
Good Luck!