I have my email clients set up to not display pictures unless I actively request them. Mostly it makes loading and displaying things faster and I have to look at less noise. It also prevents BA (and others) from tracking me.
But if you find the idea of BA monitoring when/how you read their emails worrying, then I recommend you open any website in Chrome and open the developer tools. The number of server connections that happen in the background when you open any website is pretty astonishing.