bootstrap theme with responsive images

I started this new topic for I feel I need to rephrase my previous topic.
I am using PHPRunner 9.7 build 28369 x64.

I have a Image_list page based on a table with a text field named "FN" that stores my image file names.
I use the built-in standard 'Bootstrap' project scheme with 'bootstrap' layout and 'cerulean' theme.

On top I added in Custom CSS the following code.
.bs-horizontal-value {

height: auto;

width: 100%;

}
My text field "FN" is configured as 'image' on the Image_list page.
I have presently this HTML code round my FN (image) field on my Image List page.
<DIV class="bs-horizontal-value col-md-8 {$FN_class}" {$FN_style}>

{$FN_value}

</DIV>
Now, as a result, I remark that this field is not behaving 'responsive' as expected.

I tried by changing 'bs-horizontal-value' into 'img-responsive' both in the Custom CSS as in the HTML code but to no result either.
Remark:

The result is however responsive when a clear full file name is given as in the following code:
<DIV>

<IMG class="img-responsive" src="images/myimage.jpg">

</DIV>
And also with plain text fields the result is responsive.
****
Is it known behavior in PHPRunner that the result is not responsive when using text fields to be viewed as 'image' referencing image file names as below ?



<DIV class="bs-horizontal-value col-md-8 {$FN_class}" {$FN_style}>

{$FN_value}

</DIV>
Any guidance is welcome.
Hope I have clarified my concern.