Lately I’ve been doing a ton of reading on decreasing website load time, image optimization techniques, responsive loading for different devices, and every detail I can find in between. One quick takeaway is that I will always tick the “progressive” checkbox in Photoshop’s Save for Web dialog from now on when saving JPEGs larger than 10KB.
There is no downside that I can find: progressive JPEGs tend to be smaller on average. The progressive loading experience has actually been proven to “feel” faster to a user, because they have something to look at versus watching the image paint in.
And, as Duncan Davidson and Steve Streza found out as a result of their research this evening, they look way fucking better on iPad 3s.
Bonus trivia: I’ve also recently learned that you cannot shed bytes significantly if you gzip a JPEG. It’s already completely compressed.