Apple’s Photo app is very simple to use. It combines a digital asset manager (DAM), which is essentially a tool that organizes and displays photos, with powerful editing tools. Many photographers are convinced that they need Adobe’s Lightroom and Photoshop to manage and edit their photos, but Apple’s Photos can do much if not most of what they need. (It’s the tool I use for almost all my photo editing.)
When you edit photos, and want to share them, there are two ways to save files in JPEG format. And these two methods create files of very different quality.
The easiest way to share a photo is to drag it from the Photos window to the Finder. Photos exports a JPEG when you do this. If you select a photo and click the Share button, then choose to, say, email it, the photo is saved in the same way.
But this is a highly compressed JPEG. For example, I exported a photo I shot on my iPhone SE, first just dragging it from the Photos window, then using the File menu’s Export command.
If you select the photo, then choose File > Export > Export 1 Photo, and set the JPEG quality to Maximum, you get a much larger image file, with much less compression.
If I compare the file sizes, I can see that first file is about 2 MB, and the second 7.3 MB. GraphicConverter tells me that the compression level of the first photo is 1:22, and the second 1:5.
Obviously, you may not always want the lower level of compression for your images (the higher number means more compression). If you’re sharing them on social media, or uploading them to a website, the smaller files will be better. But if you want to save your files in their best quality (assuming you don’t also have raw files), or if you want to edit your JPEG files in another app, you should always use the manual export feature.
Another point to note is the File > Export > Export Unmodified Original For… command. This exports your original files – raw and/or JPEG – ignoring any edits you may have made. With the above photo, exporting the unmodified original results in a 2 MB file. In other words, exporting it with the lowest compression saves the file in a much larger size than the original, recompressing it. This does not make the image quality any better, and only takes up more space.
Here’s another example. When I drag a photo that I shot in raw format from Photos, it saves it at about half the size of the same photo exported from the File menu.
In this case, Photos generates a new JPEG from the raw file when exporting. This file is twice as big as the dragged file, and the compression levels of the two files are 1:18 for the dragged file, and 1:8 for the exported file. (The original raw file is 50.8 MB.) And my unmodified original JPEG file (I shot this in raw + JPEG) is 13.5 MB, but it’s in color, so the 10.8 MB exported JPEG is roughly the same quality.
This is all a bit confusing, isn’t it? So here’s the takeaway:
- If you want to quickly export a file to share on social media, send by email, or post on a website, you can drag the file from the Photos window.
- If you want a higher quality file to, say, edit in another app, or to print, then use the Export feature.
- If you want to use an original JPEG to edit in a different app, use the Export feature.
- Note that exporting a JPEG with a lower level of compressing will make a file larger, but won’t make it any better if the original was not very large (i.e., an iPhone photo). To see the original file size of a photo, select it and press Command-I; the Inspector shows this.
- And if you want the best quality JPEG from a raw file, use the Export feature.