Some images do not shrink when viewed on mobile

Hi all,

I’ve spend the past few days googling this issue and with no avail. I’ve decided to see if anyone on here has seen this, and/or has a fix for me. It is driving me nuts.

So I have a site I created using the Simple Grid Theme
https://www.dessign.net/simple-grid-theme-responsive/
The page can be seen here:
https://www.comedybythegraham.com

Everything worked out great for the site design, albeit one issue. When I look at the site on a mobile device (tested on iPhone) everything on the site shrinks down correctly, minus the 3 icons on the bottom of the main page.

I have tried multiple Mobile plugins and packages and even tried changing image types from .png to .jpg as well as creating 2 smaller images and uploaded them to my images folder (at 50% and 75% of the original size)I also tried the WP-Resolutions plugin, but that bricked my site into a 500 Internal Server Error.

I am so stuck and if anyone out there can help, I will be so grateful. We can’t seem to see what is the issue.

Thanks in advance.