Do not link to full size image if image already has link

[Dmitri]

If a user uploads an image and in RTE defines a link for the image, for example to some external url and we end up resizing that image because it's larger than pre-defined width/height, we should not link the resized image to the full-size version like we normally do. Instead we just have to keep the link that user has specified. We can still add special class to the image to indicate that it's resized so in the future we can fine some way to navigate to full size image using javascript, maybe adding some menu on right-click that will show option to see full-size