I thought so too, but if you consider they removed the "from", "to", "subject" and top actions panels, the original had less content space. On the screenshot, the original had 152px of content height and the new one has 232px, ~ 150% of the old one. The one on the right shows a picture that's also content. I assume they redesigned the email thread so the box above the current email is the mail the person is responding to, with the pictures attached.