Image Slider image issue when upgrade from 8.5.7 to 9.1.0

So on Concrete 8.5.7 my stock Image Slider showed the image as a single line image <img src="/application/files/8415/9671/6988/Liquid__Pressure_Slider.jpg" alt="Shop Floats" width="2100" height="700">

After the upgrade it shows it as <li><picture><!--[if IE 9]><video style='display: none;'><![endif]--><source srcset="" media="(min-width: 900px)"><source srcset="" media="(min-width: 768px)"><source srcset=""><!--[if IE 9]></video><![endif]--><img src="" alt="Shop Floats"></picture><div id="ImageSlider">
How do I get rid of all the v9 brought and get back to the simple img src from v8? Biggest issue, besides the extra data the v9 version doesn’t take up the full width.

We’ll have to look into this a little more and follow up.

@mdius for your second question about taking up full width, I suspect that’s some extra CSS that you added to the block which is not matching the v9 block for some reason. This CSS (originally from Linuxoid) should match the block in both 8.5.7 and 9.1.0 and make the image slider full width:

.ccm-image-slider-container, .ccm-image-slider, .ccm-image-slider-inner, .rslides {
    width: 100% !important;
    margin: 0 !important;
    padding: 0 !important;

For the first question about the markup, the output is going to depend on your theme as explained here by mnakalay.

So, if you don’t want that, you’ll need to disable that in your theme or create a template which sets the usePictureTag option explicitly: Concrete\Core\Html\Image | ConcreteCMS API

It is different between v8 and v9.
v8 $tag is:
$tag = Core::make('html/image', [$f, false])->getTag();

v9 $tag is
$tag = Core::make('html/image', ['f' => $f])->getTag();

If I use the tag from v8 the image does not load. The css has not changed at all from 8 to 9.
I looked at what was posted from the links you showed and I cannot get any of the ideas to work.
But I figure out if I make:
public function getThemeResponsiveImageMap() { return []; }
That completely removed the picture tag from the full site. I am perfectly OK with this.