Picture optimisation

JPG format

JPG format is great for color and photographs, it is also important to note that there is a slight loss of quality due to compression.

Editing and re-saving only degrades the quality. One way to minimize this is to work with the RAW JPEGs, determine your edits, and then save out the final version without re-saving multiple times.

PNG format

• Ability to use transparency and or opacity, as opposed to JPG where by default it will retain a white/blank background.
• The use of color palettes. PNG supports 24-bit RGB and 32-bit RGBA colors.
• Grayscale images.

Even though PNGs use a lossless compression, they are still generally smaller when seen on the web, primarily because PNGs are commonly used for non-complex images such illustrations. JPGs are typically used for photographs which are much larger.