While I surely do not advocate capturing in JPEG, it's a given that the format is a great way to share images of reasonable size.  As our cameras become more sophisticated and have more megapixels in the sensors, the definition of "reasonable" starts to float up there, and that's the rationale behind JPEGmini.

JPEGmini comes in two flavours.  JPEG mini Pro does everything the regular version does (that I will call Diet based on the logo), plus adds the ability to run as an extension in Photoshop and a plugin in Lightroom.  It also runs 8x faster and can handle images up to 60 megapixels whereas the Diet version can only deal with images up to 28 megapixels.  

JPEG as we know is a destructive compression mechanism, but due to small image size and low resolution on the web, regular JPEG images can still look completely awesome on your display or your smartphone.  The challenge comes when you don't want to downsize or set a lower quality level in your JPEG exports because the files are going to be rather large.  I have been doing some testing on Canon's EOS-M3 and the native RAW files are running about 40mb per, so the full size JPEG exports after editing were coming in around 37mb.  That's a very large file, and moving lots of them around takes time and money.  

JPEGmini brings their own compression algorithm on top of the core JPEG compression.  They do a really good job too, because they can make the file much smaller without causing a serious compromise in quality.  If you want to post or send full sized JPEGs to people, this may be a solution for you.

I tried the evaluation download that you can get at their website to see how it would work.  I used the app as a standalone for my first test.  This was an export from Lightroom through Photoshop to apply a Digimarc invisible watermark.  The file size was 37.6mb for the full size JPEG.  After running it through the eval version of JPEGmini the file was reduced to be 18.7mb, a reduction of 2x.  I made a copy of the original, because JPEGmini overwrites your original file when you use it standalone mode, and compared the two on the screen using Apple Preview.  I could not see any difference at all on the excellent BENQ 2740 display.  This is a very nice space saving and of course reduces consumption of cloud storage and bandwidth.

The Pro version includes a Photoshop extension as well as a Lightroom plugin.  I was only using the trial version and so didn't try those out.  I did take an older export that had been reduced in size for display on the web.

This example, called Europa, showed a 3.4x reduction as you can see in this screen capture.  Thus it's safe to conclude that JPEGmini will consistently make your JPEGs smaller and no software choked on the files.  

The manufacturer, a company called BEAMR offers JPEGmini for $19.99, JPEGmini Pro for $99.99 and JPEGmini Server for $199.99/mth   The server version is targeted at large photo houses, online retailers and those who have to process potentially thousands of images every month.

You'll have to decide for yourself if the investment is worth your while.  I like the idea of the product plugging in to Lightroom and Photoshop, but I don't see the need for file size reduction enough to warrant the expenditure of $100 USD for that.  $20 USD strikes me as good enough for now, and I expect to make the purchase once the trial expires.   One can always purchase an update to Pro later on.

If you tend to upload a lot of images to social media, or to your own website and you want to push larger files without slowing performance down, JPEGmini might be exactly what you are looking for.  Download the trial and give it a shot.