Yes,
Say you wanted to insert this picture...
If you
right click this image, and then open 'properties', it will give you the image 'Location'.
So in the Signature box in your 'Profile' menu, you just copy in the image location address, and surround it with this...
immediately at the back end.
You then have to click on the
Submit box at the bottom of your profile page, and the image should then appear under all your posts.