Issue Summary

When an image is inserted into the extra properties of an alert using HTML tags it is not resized when viewing in the browser. 

Steps to Reproduce

1. Create an alert using the below values as an "extra property"

key: image
value: <img src="https://cdn.britannica.com/53/252953-050-30D00122/Mickey-Mouse-Steamboat-Willie-Walt-Disney-Public-Domain.jpg" /> 

Expected Results

When viewing the alert in the browser, the image is scaled to a reasonable size where it fits in the window

Actual Results

The image is shown at the real dimensions, causing it to extend past the edge of the alert

Workaround

You can a cap on image width using the width="Xpx" attribute, where X is the maximum width you'd like the images to be. This can be done at the integration level or using a policy to rewrite the HTML tag like so: 

<img src="https://cdn.britannica.com/53/252953-050-30D00122/Mickey-Mouse-Steamboat-Willie-Walt-Disney-Public-Domain.jpg" /> 

becomes

<img src="https://cdn.britannica.com/53/252953-050-30D00122/Mickey-Mouse-Steamboat-Willie-Walt-Disney-Public-Domain.jpg" width="400px"/> 

and the image is displayed at a reasonable width: