Even if I have {{image}} it does not show the image, just the filename. Are there any plans to be able to show the image as well? Or is it possible with any other shortcode?
Not currently. The image field stores the filename and the entry doesn’t know which field produced the value. If the entry snippets are implemented, you can control it yourself however.
I would recommend not changing the original line, but instead writing a field that is an extention of it (extend the structure class) - and while youre at it - release it as a field plugin so everyone can use it!