Thanks for that, Rod.
I had a bit more of a play around and think I have things as I want with the code below. Was able to wrap the iframe in a DIV and load a background image first (same image as the first image of the slideshow). Makes things look like it is loading faster.
My code now is:
<style>
@media only screen and (max-width: 650px){
.iframeframe_sm {
background-image: url("https://www.tasmanianphotos.com/website_slideshows/homepage_slideshow_1_sm_320_240/20200525- 091513-Ship-Stern-Bluff.jpg");
background-size: 320px 240px;
width: 320px;
height: 240px;
margin: 0;
padding: 0;
display: inline-block;
}
.sm {
display:block;
}
.lg {
display: none;
}
}
@media only screen and (min-width: 651px){
.iframeframe_lg {
background-image: url("https://www.tasmanianphotos.com/website_slideshows/homepage_slideshow_1_lg_600_450/20200525-091513-Ship-Stern-Bluff.jpg");
background-size: 600px 450px;
width: 600px;
height: 450px;
margin: 5;
padding: 0;
float:left;
margin-right: 20px;
display: inline-block;
}
.sm {
display:none;
}
.lg {
display:block;
}
}
</style>
<div class="iframeframe_lg">
<iframe class="lg" src="https://www.tasmanianphotos.com/website_slideshows/homepage_slideshow_1_lg_600_450/" style="width: 600px; height: 450px; border: 0;"></iframe>
</div>
<div class="iframeframe_sm">
<iframe class="sm" src="https://www.tasmanianphotos.com/website_slideshows/homepage_slideshow_1_sm_320_240/" style="width: 320px; height: 240px; border: 0"></iframe>
</div>
Let me know if you see any issues with the CSS above - but appears to be rendering all ok on the computer screen and phone now.
Cheers,
Chumby