Here is the screen shot of mapping of my FCE:

I can refer 'Caption' field by 'field_caption' from the typoscript of 'Link' field.
Here is the typoscript for that:
10 = TEXT
10.field = field_caption
How to refer the 'Image' field which is inside a container field 'Image and alternate text' From the typoscript of 'Link' field?
I tried to refer it directly by using 'field_image', but it is not working.
here is the screen shot:

Markup I am trying to map is:
<a href="resources/img/site/demo1.jpg">
<img src="resources/img/site/demo1.jpg" alt="alternate text" />
<div class="flex-caption">
<p>caption text</p>
</div>
</a>
Ok, you want to wrap the image with a link. Actually you have to do it the other way round.

In my case the span link
has display:none;
because it's my link placeholder. In your scenario it is field_link
.
Now click to edit your field_image and click on data processing. Edit TS Code:
10 = IMAGE
10.file.XY = 200,150
10.file.import = uploads/tx_templavoila/
10.stdWrap.typolink.parameter.field = link
This last line wraps the image with a link. In your case it would be
10.stdWrap.typolink.parameter.field = field_link
来源:https://stackoverflow.com/questions/12913835/typo3-fce-refer-a-field-inside-a-container-field