Link
I can see these mini images, too.
It's ok with mPDF, so domPDF seems to miss something.
The image size is ok (in details PDF) if you set "PDF Bootstrap"=no in form [Layout] settings.
But I assume then some other CSS may be missing.
So we have to find which CSS rule must be added to get the image size correctly in DomPDF...
Edit:
For fileupload images:
Modify (or override) plugins\fabrik_element\fileupload\layouts\fabrik-element-fileupload-image.php, line 5 (set style= instead of HTML4 height=)
Code:
$height = empty($d->height) ? '' : ' style="height:' . $d->height . 'px;width:auto;" ';
