What is the difference between png and jpg

png and jpg are two common image file formats. They differ in the compression, quality and transparency of the image.

First, let’s take a look at their compression methods. JPG (also called JPEG) uses a lossy compression algorithm to reduce file size by reducing detail and color information in the image. This compression method can significantly reduce file size, but will lose some detail, especially at high compression ratios. PNG (also called Portable Network Graphics) uses a lossless compression algorithm, which does not lose any image details and retains all pixel information with higher quality. Therefore, PNG files are usually larger than JPG files.

Secondly, let’s take a look at how they handle color. JPG files use a color space based on the RGB (red, green, and blue) color model, which is very suitable for true color images. In addition to supporting RGB color mode, PNG files also support more color modes, such as indexed color and grayscale color. This makes PNG files more flexible in handling image transparency and color richness, and performs better on images that need to retain shadows, transparent backgrounds, or color gradients.

Then, let’s take a look at how their transparency is handled. JPG files do not support transparency, and certain areas of the image cannot be set to be transparent and can only appear as white or other specified fill colors. PNG files support transparency, and you can set certain parts of the image to be transparent for compositing with other images or backgrounds. This makes PNG files very useful in situations where a transparent background is required, such as web design, icon design, etc.

Finally, let’s take a look at their application fields. Because JPG files have the characteristics of smaller file size and high compression rate, they are widely used in scenarios that require fast loading and save storage space. For example, when displaying a large number of pictures on a web page, JPG files are the preferred format because it maintains a good balance between color effects and file size. PNG files are more suitable for use in scenes where details, transparency and color richness need to be preserved, such as designers' original design drafts, printed matter, etc.

To sum up, PNG and JPG are two different image formats, and they have differences in compression, quality and transparency. Which format to choose depends on specific usage scenarios and needs. For images that need to maintain high-quality details and transparency, choosing the PNG format is a better choice. For images that need to be loaded and stored efficiently, it is more appropriate to choose the JPG format.

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