Question: Are there ways to resize an image to fit thew window the image is being viewed in *WITHOUT* javascript and limited CSS? 

I ask because I have an email campaign that I send out that features a main image that I want as large as possible *without* scrolling. I have read ways to do this with javascript and jQuery but I do not see a way to do this that the majority of email clients will read and react to properly. Is this possible? And if so - How?

Answer: 
You need to be as archaic as possible to make HTML emails work across all clients. 

Inline styles and HTML 4 code should do the trick. Be warned though - max-width and max-height works in most clients, but this does NOT include Outlook 2007/2010/2013/365 which could well be over half of your target audience. Width works in all clients - but NOT on div and p tags in Outlook 2007/2010/2013/365! Always use tables not divs to be certain it will work.

Basically, always assume something isn't going to work and design for the smallest possible margin for error - and ALWAYS use inline styling or it might well get stripped.

If in doubt consult the oracle, I always do :)

Source: <https://www.campaignmonitor.com/css/b/>
I was dealing with really big images without any kind of a container. I fixed it by using `max-width` to ensure the image wouldn't be too big.

```
    <img
        src=""
        width="100%"
        style="max-width: 80vw; margin: 0; border: 0; padding: 0; display: block;"
    />

```

Using both width and max-width ensures the image will take the full available space, but not too much. I used `80vw` and not `100` because people rarely read your emails in a fullscreen mode, usually more often using a viewer (Gmail), which usually uses a bit of the available space.