In our old template we could use images of different sizes and resize them as they got added to the email so they would all appear uniform. Now that we know we have lost this functionality, we know we have to upload images in their final size, which is often an extra step.
Thank you for following up with these details. I took a look at your account and can see many of your templates are both in our newest Third Generation Newsletter Templates and our older Second Generation Legacy Templates. Many of our Legacy Templates are mobile-friendly template and not mobile responsive. A mobile responsive templates will resize based on the screen size of the device. While on the other hand, a mobile-friendly template does not change based on the device being used. I apologize for any inconvenience caused from the difference in these templates. We have successfully tracked your feedback on this in the meantime.