Missing icons in Safari and Chrome

I am running High Sierra 10.13.2 on an iMac and some icons and links in Safari and Chrome appear as squares or have disappeared all together from certain webpages. This was also happening with Sierra 10.12.6 Below are some examples of the problem.Here is a photo from Google Calendar in Chrome where icons appear as squares, like the date forward and backward arrows or the search icon or settings icon. Below is an image from Safari where everything appears as normal.

Here is an image of Pixieset in Safari and Chrome where icons are completely invisible. There should be icons in the top tool bar next to collections, store etc. and in various other places. Below is an image of how the website should look taken in Safari on an iPad.Any ideas?