How I increased my conversion rate 56% on Shopify. Hint: Image Optimization

Smaller is better & faster. There's no noticeable difference in image quality.

So my A/B test is 4 months before vs. 4 months after. This is not a small sample size. It's around 500k uniques on each end. 3M+ page views on each end.

I've also broken & analyzed the traffic down by channel, new vs return, and any other way I can to attempt to remove any false positives. From all the data, the large increase in conversion was because of this particular change.

I have been aware of "holiday shopping bias" around nov / dec, but January is normally a very shitty month for conversions. January / Feb our conversion was higher than any previous month before this as well.

This is actually why I've waited to Feb to really solidify the results in my own mind. And that's why there's 4 months of data to back it up. Every day since the change, being better than before.

I don't need to A/B test this one. The savings on my homepage was 4MB. We're not talking small bytes here. This is a major issue with regards to anyone using Shopify.

See if you can guess which month the change happened on this chart: http://i.imgur.com/S95EX9Q.png

Because I can see it.