[TYPO3] Minimal TS code to pull IMAGE from tt_content.image?

[Martin Bless]

I want to render a  tt_content.textpic object differently. What I
don't understand and I'm not achieving yet:

Instead of pulling an image from a file, as in

temp.1 = IMAGE
temp.1.file = fileadmin/img/cool.jpg

I want to pull the first image from the tt_content.image field, that
is to say (WANTED):

temp.1 = IMAGE
temp.1.file = [ give me first image of current tt_content.image ]

Is that possible? What's the minimal TS code?

Maybe the problem is that I simply don't understand the code in
styles.content.imgtext which starts like this:

styles.content.imgtext = IMGTEXT
styles.content.imgtext {
  imgList.field = image
...

What does "current" do?

Martin