Image Compression

What is image compression?

Image compression is a process for reducing the size of a digital image without sacrificing its visual quality below a certain threshold. Individuals and businesses use image compression to save storage space and reduce transmission time when sharing content over the internet. Photographers and web designers are examples of roles that may benefit from image compression due to the volume of image data they work with. 

Tools like image optimization software make delivering high-quality website images easy while keeping the smallest possible size for the best results. An image’s dimensions, size, format, and resolution are optimized automatically as part of the image optimization process. 

Types of image compression

Two primary image compression methods are available depending on the specific use case and desired outcome for the image. The two types are:

• Lossless: When leveraging lossless compression techniques, the size of an image is reduced without any loss of overall image quality. When the receiver of the image decompresses a compressed image using lossless techniques, they see a replica of the original image. 
  Lossless compression uses an algorithm to shrink the image by rewriting the file to make it more efficient. This method is preferred when maintaining image quality is of utmost importance, such as in graphic design. Some examples of lossless compression formats include Graphics Interchange Format (GIF) and Portable Network Graphics (PNG). 

• Lossy: When a slight loss of image quality is acceptable, folks may use lossy compression techniques. Loss compression reduces the size of an image by discarding some of the less critical image details, which results in a smaller file size. A smaller file size can sometimes lead to a slight reduction in image quality, which may or may not be noticeable to the naked eye. 
  Lossy compression is best suited for tasks like updating websites to create faster load times and sharing an extensive library of small images. Some examples of lossy compression formats include Joint Photographic Experts Group (JPEG) and WebP. 

Benefits of image compression

Image compression techniques offer several advantages in various digital imaging scenarios. Some of the key benefits of image compression include the following:

• Reduced storage or disk space: The main benefit of image compression is that it significantly reduces the size of image files, freeing up disk space and creating more room to store additional files. 

• Faster data transfer times: Smaller image files reduce the data needed to transmit images over the internet. For example, image compression makes web page loading times quicker and easier for sending large email attachments. Faster data transfer times reduce bandwidth usage while simultaneously improving the user experience. 

• Potential cost-savings: Storage space and solutions can be costly. Since image compression frees up storage space, it can save costs as less storage space may be needed over time. Businesses and individuals handling large databases of image files should experience significant cost benefits.

Challenges of image compression

While image compression provides significant benefits regarding storage space, data transfer times, and cost savings, there is a trade-off. The challenges of image compression to consider are:

• Loss of image quality: Lossy compression techniques result in a loss of image quality due to significant file size reduction. While it may not be noticeable in some instances, the more an image is compressed, the more prominent the quality shift will become. This is not ideal when the highest quality, such as in medical imaging, needs to be maintained.

• Loss of data: In lossy compression, less critical data is discarded to reduce the file size. This could lead to the loss of subtle details and nuances, which may be less favorable in specific contexts. Once an image is compressed, the lost data can’t be recovered, and without an uncompressed backup, the high quality is gone forever. 

Image compression best practices 

Effective image compression requires striking a balance between reducing file size and maintaining quality. Individuals and businesses should consider the following best practices to achieve the highest likelihood of success when compressing images:

• Backup images before compressing them. Before applying compression techniques, it’s crucial to keep uncompressed backup copies to revert to the original quality when needed. This step is critical before using lossy compression techniques, as data gets deleted permanently. 

• Choose the suitable compression format for the scenario. Consider whether lossy or lossless compression formats would be best. As a general rule of thumb, lossless compression is best when preserving image quality is the highest priority. Lossy compression formats may be the better choice when reducing file size is the highest priority, so long as some quality loss is acceptable. 
• Edit and preprocess images before compression. If an image requires some editing, such as enhancing colors and contrast or retouching parts of the image, complete the edits before compressing the image. Editing a photo after it has been compressed could further reduce the image quality. 

Improve quality and refine photos before compressing them with these photo editing tips.