Where can I get a thorough education on saving to the JPEG file format?

[Ken Nielsen]

1. JPEG is probably the most popular file format I use, saving to social media mainly and then other use online on the web. As my screen shot attests, there is more to this file format and I want to learn. For instance, the side note you see on the screen shot says that there is more to 'saving options' but I don't know how to acces this advanced saving criteria. Also, even what I have posted for a screen shot shows 'dimmed' areas that I don't know how to access even if I knew what they were for. Bottom line, I am sadly weak in my understanding of how to properly set up JPEG's for posting online, let alone for this file formats many other uses. Where can I get the wholde story on all of this file format's capabilities and control settings?
   

[TheDigitalDog]

https://jpeg.org/jpeg/

https://helpx.adobe.com/photoshop-elements/using/optimizing-images-jpeg-format.html

http://regex.info/blog/lightroom-goodies/jpeg-quality

[Ken Nielsen]

Thank You. My New Year's Resolution: to be better aquainted with the jpeg format and to be able to use it intelligently. You have me off to a great start now!

[Stephen_A_Marsh]

@Ken Nielsen 

To address your specific question on 8 bpc vs. 16 bpc Save As a Copy:

Save As/Save As a Copy will include the most metadata in a JPEG file, while the old Export > Save for Web (Legacy) option and the "new" Export As/Quick Export As feature is designed to remove or only offer limited metadata in the saved file for the smallest file size (they all use different algorithms). Compare the file sizes and compression values from left to right, one row at a time:

Photoshop 2021
Save As		Save for Web (Legacy)		Export As
Save As JPEG, Level 12 Baseline Standard	3,382,351 bytes (3.4 MB on disk)	Save for Web (Legacy), Quality 100	3,035,739 bytes (3 MB on disk)	Export As, Great (7)	2,951,329 bytes (3 MB on disk)
Save As JPEG, Level 11 Baseline Standard	2,549,259 bytes (2.6 MB on disk)	Save for Web (Legacy), Quality 92	2,520,944 bytes (2.5 MB on disk)
Save As JPEG, Level 10 Baseline Standard	2,072,956 bytes (2.1 MB on disk)	Save for Web (Legacy), Quality 84	2,128,221 bytes (2.1 MB on disk)
Save As JPEG, Level 9 Baseline Standard	1,813,312 bytes (1.8 MB on disk)	Save for Web (Legacy), Quality 76	1,826,102 bytes (1.8 MB on disk)	Export As, Excellent (6)	1,835,030 bytes (1.8 MB on disk)
Save As JPEG, Level 8 Baseline Standard	1,597,234 bytes (1.6 MB on disk)	Save for Web (Legacy), Quality 68	1,579,870 bytes (1.6 MB on disk)
Save As JPEG, Level 7 Baseline Standard	1,245,822 bytes (1.2 MB on disk)	Save for Web (Legacy), Quality 60	1,301,819 bytes (1.3 MB on disk)	Export As, Very Good (5)	1,324,234 bytes (1.3 MB on disk)
Save As JPEG, Level 6 Baseline Standard	905,668 bytes (909 KB on disk)	Save for Web (Legacy), Quality 52	1,173,631 bytes (1.2 MB on disk)
Save As JPEG, Level 5 Baseline Standard	837,439 bytes (840 KB on disk)	Save for Web (Legacy), Quality 44	742,928 bytes (745 KB on disk)	Export As, Good (4)	695,320 bytes (696 KB on disk)
Save As JPEG, Level 4 Baseline Standard	786,204 bytes (786 KB on disk)	Save for Web (Legacy), Quality 36	658,904 bytes (659 KB on disk)
Save As JPEG, Level 3 Baseline Standard	740,953 bytes (741 KB on disk)	Save for Web (Legacy), Quality 28	596,724 bytes (598 KB on disk)	Export As, Fair (3)	590,963 bytes (594 KB on disk)
Save As JPEG, Level 2 Baseline Standard	753,850 bytes (758 KB on disk)	Save for Web (Legacy), Quality 20	546,622 bytes (549 KB on disk)	Export As, Poor (2)	563,817 bytes (565 KB on disk)
Save As JPEG, Level 1 Baseline Standard	709,518 bytes (713 KB on disk)	Save for Web (Legacy), Quality 12	437,863 bytes (438 KB on disk)	Export As, Very Poor (1)	498,396 bytes (500 KB on disk)

[Ken Nielsen]

Thank you Stephen, Now I've got what I've wondered about for eons but am always in the middle of a project and too busy to stop and find out. As a last area, I know the jpeg format does not support transparency but what is that reference to 'matte' that is dimmed in my screenshot but is not dimmed in your screenshots? Appreciation!

[Stephen_A_Marsh]

@Ken Nielsen - The matte option is explained in the link that @TheDigitalDog posted:

https://helpx.adobe.com/photoshop-elements/using/optimizing-images-jpeg-format.html

[Ken Nielsen]

Thanks.