Ever since I published my JPEGmini review and subsequent articles like the last one on reducing backup storage needs, I have received some emails and comments from concerned readers, who do not understand the point of using JPEG compression software, particularly when there are other existing commercial or free tools available. In this article, I would like to address some of these concerns and explain the strengths and weaknesses of the JPEGmini software.
JPEGmini vs Photoshop
One of the biggest sources of confusion in regards to JPEGMini comes from its compression algorithm. Some people wrongly believe that JPEGmini somehow uses a more advanced compression algorithms than Photoshop when dealing with JPEG images, resulting in smaller files. While JPEGmini certainly does have its software algorithm to decide on the best way to compress an image, the JPEG compression algorithm itself is not much different than what you would find in pretty much any other software, including Photoshop. You can certainly yield very similar results with Photoshop, if you have the time and patience to run through a number of different compression levels, then doing an analysis / comparison between the different outputs to try to decide which compression results in the least amount of banding / posterization and the least JPEG artifacts. At the end of the day, a JPEG file is already compressed and unless you are doing some advanced pixel approximation technique to try to reduce the total number of used colors in an image, you are basically down to simple compression levels. In Photoshop, you can go from 0% quality to 100% quality (or on a scale from 0 to 12) to determine the amount of compression used for a JPEG image. JPEGmini works very similarly in this regard and its baseline is the first JPEG already created by the software.
If you are dealing with a single image and your source is a RAW file or a TIFF file with more than 8 bits of data, your resulting JPEG image from Photoshop is going to give you the best output in terms of image quality. But how do you decide on the balance between the best image quality that does not bloat up the image in terms of total size? To reduce the potential for artifacts and banding / posterization in images, many photographers end up exporting images at 100% quality, which translates to practically no compression. The end result is massive JPEG files that are unnecessarily bloated. Those who understand JPEG compression advantages will often pick a compression number like 70% or 77% (see this article to understand these numbers), which translates to Photoshop’s 9-10 JPEG compression scales. Such levels often yield a great balance of image quality and size, which is why many of us end up picking those numbers. However, images are not created the same. On some images, there are a lot of details and very little bands of uniform color, while in other images, there are far fewer details and more uniform colors. Picking a single number for compression in such cases is not ideal – even 77% can result in unnecessarily large files. This basically means that a single compression level for all images is not ideal – you are always better off assessing each image individually and deciding on what compression level works best for that particular image. And this obviously translates to a lot of time experimenting with different compression levels for each image. This evaluation process can certainly work out for an image or two, but can you image trying to do this on hundreds of images? Good luck with that! And that’s the whole point of JPEGmini in the first place.
JPEGmini File Analysis
The main point of using JPEGmini is to analyze each individual JPEG file and decide for the best compression algorithm for that particular file. If a file contains a lot of detail and has practically no potential for compression, JPEGmini applies very little to no compression. Whereas if there is good potential for compression without adding artifacts, it applies aggressive compression. And this all has to happen without adding artifacts that can be distinguished by your eyes!
Let’s take a look at one sample image and see what my preference of 77% compression does compared to what JPEGmini decides on an image exported at 100% quality. Here is a before and after – the before is 77% quality export, while the after is what JPEGmini did to the image:
Obviously, you cannot see any difference between the two files and that’s the whole point of JPEGmini – there should be no visual difference!
However, there is a pretty significant difference in image size. The image that Lightroom exported at 77% quality is 617 KB in size, while the image that JPEGmini compressed is only 371 KB. That’s a whopping 166% in space savings. Clearly, JPEGmini is applying more aggressive compression than 77% on this file. So what if I reduced compression by one level to 62%? It still resulted in larger file size – 425 KB to be exact. Only after I moved compression down to 54%, the image size got somewhat similar, roughly 345 KB total. Here are the two compared – “Before” is Lightroom export at 54% and “After” is JPEGmini:
I still see no difference between the two, so we know that JPEGmini’s compression is equivalent to Lightroom / Photoshop’s 54% JPEG Quality.
And if I pick a totally different image with more or less details, the results will change completely. Here is another image that I exported then compressed with JPEGmini compared to an image exported from Lightroom at 69% Quality:
If we look at these two images and their sizes, we can see that they are more or less equivalent – JPEGmini image is 325 KB, while Lightroom image is 339 KB. This means that JPEGmini chose a compression level of roughly 69% for this particular image, which is quite different than the compression level it chose for the previous image (54%). And depending on what image you pick, things are going to vary – images will compress less or more depending on what’s in the image.
JPEGmini Batch Process
Now let’s try to evaluate how much effort we would need to land with the same results. I would have to export the same image at different compression levels from Photoshop or Lightroom, then open each one individually to see where the image starts to get damaged. I then have to pick that one level as the most desired level of compression. With JPEGmini, I export all images at 100% quality and let the software do the rest. Yes, it is that simple. I never have to worry about losing image quality and I know that each image the software spits out will be the most optimal in terms of size.
JPEGmini’s power is not centered around a single JPEG file. Its main advantage is the ability to batch process a lot of images. I have previously shown an example of how JPEGmini was able to optimize my entire catalog’s of JPEG images, saving me a whopping 84 GB of storage:
And that’s for a person who shoots RAW! I can only imagine what the software would do for people with a lot of JPEG images – sports, wildlife, news, portrait photographers to name a few – those could all hugely benefit from such software. And in the corporate world, all those property photos, product photos and holiday parties – I bet they are captured at 100% quality JPEG and never touched again. Think of how many dentists could benefit from JPEGmini! All those photos of teeth captured at maximum resolution are just sitting there occupying space. And did I mention that JPEGmini can actually resize images to lower resolution as well? Yes, you could run through the entire catalog of photos and resize them to say 4K resolution:
So if you don’t need full size JPEG images, you have that option too.
JPEGmini Does NOT Touch EXIF Data or Color Profiles
There are lots of JPEG compression tools out there and JPEGmini is far from being the only one. I have taken a look at a number of options before that are meant to make JPEG images smaller in size. None of them do it “smartly”. Most either give you the option to apply additional compression (same level for all images), or do it for you. And most of the ones that claim to make JPEG images smaller also strip out a lot of information from JPEG files, including EXIF data and color profiles. The latter two are important for me, because I do want to preserve EXIF data in my images. EXIF not only stores exposure information, which is something I want to provide to our readers, but it also stores copyright information. And losing color profiles in JPEG images is not an option either, because the colors will no longer look right.
When JPEGmini optimizes images, it never strips EXIF data or Color Profiles, making it safe to use for uploading images to the web.
Hope this answers many of the questions and queries regarding JPEGmini from our readers. Please let me know if you have any questions!