The other day I wrote a post about Guetzli, the new open source JPEG encoder from Google which promises to reduce file sizes by at least 35% without losing image quality. At the end of that post I briefly mentioned ImageOptim, which is a free Mac application that does lossless image compression. I’ve been using ImageOptim for years and absolutely love it. It normally takes 5 to 6 percent off of size of image files. Everything I publish on this blog I run through ImageOptim before uploading.
Today I emailed the developer to ask if he was looking at integrating Guetzli into a future version, he quickly responded and let me know he had already implemented it into the latest beta. Say no more.
I downloaded the beta, installed it, and then activated Guetzli in the applications preferences. I took a recent picture that I had published on this blog and threw it in:
The process is slow, like it says in the screenshot. I did not time it, but I think it took as much as 5 minutes, which is a stark difference. Normally ImageOptim takes just seconds to run. Looking past the time it took to encode the new JPEG file the result is absolutely amazing. A 55% reduction in file size. It took a 2.2MB file and turned it into a 1MB file.
I compared the original image file to the file created by ImageOptim and from my what I can see they are nearly identical. The difference is so minimal that the average person would never notice it. It’s an absolutely amazing result.
Then I decided to try another image in order to see if I would get similar results. Since I had tested it on an image that was already resized to go on the web (2080 pixels) I decided to try it on a JPEG that had not had it’s pixel dimension reduced. I took a file that was 8.5MB (4288×2848 pixels) and ran it in ImageOptim.
Again the result is an amazing 58% reduction in file size. It took the JPEG down from 8.5MB to 3.5MB.
I really can’t state enough how impressed I am with these initial results. Guetzli seems to be the real deal, offering compression that makes a real difference in a format that is already widely adopted and in use.
Go and check it out for yourself.