How do you choose between lossy and lossless image compression?

1 Lossy compression

Lossy compression is a type of image compression that discards some data from the original image, resulting in a smaller file size but also a lower image quality. Lossy compression is suitable for images that do not require high fidelity, such as web graphics, social media photos, or video streaming. Some common lossy compression formats are JPEG, GIF, and MPEG. The main advantage of lossy compression is that it can achieve high compression ratios, meaning that it can significantly reduce the file size without losing too much perceptual quality. The main drawback of lossy compression is that it introduces artifacts, such as blurring, blocking, or ringing, that degrade the image quality and may be noticeable to the human eye.

2 Lossless compression

Lossless compression is a type of image compression that preserves all the data from the original image, resulting in a larger file size but also a higher image quality. Lossless compression is suitable for images that require high fidelity, such as medical images, scientific images, or digital art. Some common lossless compression formats are PNG, TIFF, and BMP. The main advantage of lossless compression is that it maintains the exact quality and details of the original image, without introducing any artifacts or errors. The main drawback of lossless compression is that it can only achieve low compression ratios, meaning that it cannot reduce the file size by much and may require more storage space or bandwidth.

3 Factors to consider

When choosing between lossy and lossless image compression, you need to consider several factors, such as the purpose, the audience, the format, and the trade-off of the image. The purpose of the image refers to what you want to use it for, such as displaying, printing, editing, or archiving. The audience of the image refers to who will see it and how they will perceive it, such as casual viewers, professional users, or experts. The format of the image refers to the file type and the compatibility with different devices and platforms, such as web browsers, mobile phones, or software applications. The trade-off of the image refers to the balance between the file size and the image quality, and how much you are willing to sacrifice one for the other.

4 How to choose

Based on the factors mentioned above, you can choose between lossy and lossless image compression by following some general guidelines. If you want to use the image for web purposes, such as online sharing, posting, or viewing, you can opt for lossy compression, as it will reduce the file size and speed up the loading time, and the image quality will be acceptable for most viewers. However, if you want to use the image for print purposes, such as publishing, printing, or scanning, you should opt for lossless compression, as it will preserve the image quality and details, and the file size will not matter as much. Similarly, if you want to use the image for editing purposes, such as cropping, resizing, or applying filters, you should opt for lossless compression, as it will allow you to modify the image without losing any information or introducing any artifacts. However, if you want to use the image for archiving purposes, such as storing, backing up, or transferring, you can opt for lossy compression, as it will save you storage space and bandwidth, and the image quality will not degrade over time.