Summary and Recommendations for the JPG-Format
JPG-files are very efficient to reduce the size of image files and cleverly adjusted to human perception. E.g. color information is stored with lower resolution than brightness.
For photos having only few small details (e.g. sky, clouds) the compression is more effective than for images rich in small details (e.g. trees full of leaves).
Visible losses of quality are irrelevant for JPG images not using too much compression.
It is normal if you have difficulties to recognize the losses of quality in the sample images and possibly needed to move close to the monitor and squint the eyes while comparing the samples.
The sample image on the starting page and shown again here is exaggerating, using the worst JPG quality you can get in the right half.
The level of compression can be selected in image processing software and many digital cameras.
- In best possible JPG quality you will notice significantly smaller files but no visible loss in quality.
- In good JPG quality you get again a lot smaller files with almost no visible loss in quality.
- On a scale going up to 100 a value of 80 is a good choice and my standard setting.
- If you compress further you will see artifacts especially around sharp edges, tiny details disappearing and a small blocks of artifacts.
The settings I have seen on digital cameras where always in line with „good JPG quality“, even when I chose the highest possible compression.