Disappearing images once page has loaded

Hi,

Some of the pictures on my site shrink and then eventually disappear once the page is loaded. This occurs on the Front page, the ‘Services’ page and also the linked pages to the ‘Reviews’ page. (I will link to these pages and their code later)

This does not happen on all computer screens, but only some. It happens for example, on my laptop, which is a Lenovo T440 ThinkPad, intel CORE i5 vPro, using the internet explorer version 11. It does not, however, happen on my ipad 2.0. I have also tried opening the pages on a mac, and some pictures shrink initially, but then stop and adjust to the correct size.

The theme I am using is evolve, and I have a suspicion it might be something to do with the html I have put in, in order to adjust the images to the same size and layout, even though the underlying images themselves that are uploaded to the image file are all different shapes and sizes.

Sorry if this is a bit of a strange problem, if anyone could help that will be great ?? I will include the code and links relevant below:

Front page:
https://www.hillmangardens.com/
The 4 small images at the end of the text sometimes all shrink and disappear.
The image of the face to the right hand side of the page, however, never disappear.
(I have not edited the html code on this page)

Reviews page:
https://www.hillmangardens.com/reviews/
The small icons to the left hand side of each of the 3 top quotes are also problematic
(I have not edited the html code on this page)

Individual pages:
https://www.hillmangardens.com/reviews/ex-local-authority-tyburn-lane/
https://www.hillmangardens.com/reviews/ready-for-sale-findlay-property-investment-broadway-market/
https://www.hillmangardens.com/reviews/new-build-circular-wall-and-path/
https://www.hillmangardens.com/reviews/family-house-lawn-patio-and-planter/
https://www.hillmangardens.com/reviews/fence-and-new-lawn-leconfield-rd/
Pretty much all images shrink.
I have adjusted the code of each of the images, so to make them all the same size (may be different from the original file upload)…I have included a portion of the html code for the first linked page:

<a href="https://www.hillmangardens.com/wp-content/uploads/2015/04/photo-1-copy.jpg"><img class="wp-image-56" src="https://www.hillmangardens.com/wp-content/uploads/2015/04/photo-1-copy-300x224.jpg" alt="photo 1 copy" width="500" height="400" /></a>
<p style="text-align: center;">before work commenced</strong></p>

<a href="https://www.hillmangardens.com/wp-content/uploads/2015/04/photo-1.jpg"><img class="wp-image-54" src="https://www.hillmangardens.com/wp-content/uploads/2015/04/photo-1-1024x765.jpg" alt="photo 1" width="500" height="400" /></a>
<p style="text-align: center;">the finished result, view 1</p>

I can give more information if this is not the relevant sort.

Thanks!