Difference between jpeg and png files

As a general rule, the higher the compression rate of a JPG photo , the worse the quality becomes. Image-editing programs specify compression as a quality value. However, the relationship between the compression level and file size is not linear. Even small amounts of compression that barely affect quality can significantly reduce the file size.

For example, the photo below has an uncompressed size of Even with the quality setting of 95 shown here, the file size is reduced to 1. For most cameras and smartphones, 95 is the standard quality setting for saving photos in JPG format. Compressing the photo to a quality setting of 60 reduces the file size to KB, which is about 15 percent of the size of the version with a quality setting of The difference is barely noticeable in the photo:.

Higher compression significantly reduces the image quality, whereas the file size is only slightly reduced. When the quality setting of the photo is reduced to 25 , rings become clearly visible in the blue sky, and the color gradient is no longer uniform.

When the photo is magnified , JPEG compression artifacts are visible even at medium quality settings, as the example below shows.

The magnified image shows that compression artifacts are most prominent in monochromatic areas and around high-contrast edges. For this reason, the JPG format is not suitable for solid-color graphics, screenshots, and icons. A very large photo can take a while to load depending on the performance of the system and the transfer rate. JPG photos consist of coefficients, or 8 x 8 blocks of pixels, which are normally stored one after the other.

This means that the image is loaded one line at a time. In the case of a progressive JPG , the average color value of each coefficient is stored first. In this way, a blurry, pixelated image can be displayed almost immediately. Color information is then loaded for a quarter and a sixteenth of each coefficient. Gradually, the image quality gets better and better.

If you scale an image or apply a color filter or special effect, the image will be recompressed the next time you save it, which degrades quality. Any lost edge contrasts or colors can no longer be recovered. Compression artifacts are amplified whenever you go back and try to sharpen an image. However, the image-editing software must support this feature. Otherwise, quality will be lost when the image is recompressed.

Some programs even allow you to crop rectangular sections without recompressing the cropped section when you save it. When you create almost any type of software documentation, you often need screenshots. Android smartphones also automatically save screenshots in PNG format. Screenshots contain precise, straight lines with clear contrasts and monochromatic areas without color gradients. PNG, including when to use them and why. First, what type of image is it? Is it a casual picture of your dog, or a detailed graphic with a professional purpose?

Second, how do you plan to use this image? Will it be published on a company website? Or, will it be for your own personal use? The group realized a need to make large photographic files smaller, so that they could be more easily shared. Some quality is compromised when an image is converted to a JPG. The reason is because the compression is lossy , which means that certain unnecessary information is permanently deleted. Beyond the initial saving as a JPG, there are tools that will allow you to shrink the file further.

This is useful for web images, as the smaller size will increase the speed at which the page loads. As broadband internet connections become more universal, this is becoming less of an issue.

PNG pronounced as ping is a file format developed as an open solution for the patented GIF file format. PNG was developed for transferring images through the internet, and not for high quality print purposes. PNG is a raster graphics format with lossless data compression. Grey scale images with or without alpha channel and full-colour non-palette-based RGB images with or without alpha channel are also supported by PNG format. Since it is not developed for print purposes it does not support colour schemes such as CMYK, which are commonly used in the printing industry.

PNG can be used for repeated editing and does not lose data during successive editing.