When you have to send someone a large image file through email, it’s a good idea to resize the image file to make it smaller before sending it. Outlook makes this easy and allows you to resize the image file as it’s sent.
Some companies and email services still have small attachment limits. So, resizing images can avoid having your message bounced back to you.
It’s also an easy way of resizing images for yourself. Simply email the image file to yourself and have Outlook resize it automatically.
Read the full article with instructions on how the feature works at HowToGeek.com.