9 Best Ways to Compress Images in Bulk [+ Resize and Optimize in Bulk]

The use of numerous images requires image compression to save space. But, compressing one image at a time would take months to be optimized and compressed correctly.

Likewise, you will need specific tools and techniques to compress images in bulk.

Compressing images is one way of optimizing them. It reduces their size without significant loss of quality.

Small, compressed images…

  • Occupy less storage space
  • Reduce bandwidth usage
  • Contribute to faster loading times, improving user experience
  • Faster transmission over networks

When dealing with a  large volume of images, you need smart hacks for faster and streamlined compression. 

Bulk image compression involves reducing the file sizes of many images simultaneously. It enables you to automatically compress images in large quantities while maintaining acceptable visual quality.

This article will show you the best and most practical ways to quickly and efficiently compress images in bulk.

9 Best Ways to Compress Images in Bulk

Due to the large number of images involved, bulk image compression requires more attention than standard image compression.

You’ll have to start over if you make a mistake while compressing images in bulk. Thus, you need to be careful while compressing images in bulk.

Here are some of the best ways to compress images in bulk,

#1. Convert Images to the Appropriate Format

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Before you compress images in bulk, convert them to an appropriate file format. The choice of format directly impacts the image file size, image quality, and compatibility with different platforms.

When selecting the format to convert to, consider the image’s transparency, color depth, and quality requirements. The most common formats for digital images include;

  • JPEG (Joint Photographic Experts Group): JPEG (also JPG) is a lossy compression format. Its quality reduces with the file size because it discards some image data to achieve compression.

    JPEG is the best choice for web images and photographs with complex color gradients. If the images you’re compressing have transparency or sharp edges, JPEG is not the best choice as it doesn’t support these features.
  • GIF (Graphics Interface Formats): GIF is a lossless format that supports both static and animated images. If you’ve seen short animations online, they were most likely GIFs. The format also supports transparency but has a limited color palette.
  • PNG (Portable Network Graphics): Think of PNG as an improvement of GIF. It is a lossless format that supports transparency and can display millions of colors. PNG is the best choice for images with detailed graphics and sharp contrasts like graphics and logos.
  • WebP: This modern image format supports lossy and lossless compression without compromising image quality. It supports transparency and animations, resulting in smaller image sizes than JPEG and PNG.

The ideal choice of format depends on the type of images you’re compressing, the level of quality you desire, and how you intend to use them.

WebP combines all the advantages of the other formats in one format. This is why it’s gaining widespread adoption in web design, digital advertising, and other online uses that require image optimization.

#2. Resize Images Before Compressing

Resizing involves reducing image dimensions, i.e., length and width. It results in a proportional reduction in the number of pixels and, consequently, the file size.

Determine the specific dimensions you want based on the type of images you’re resizing. For example, website images like product and background images have specific optimal dimensions.

Batch resize images with,

For WordPress, use WordPress resizing plugins. These are usually image optimization plugins with features for resizing and compression. Here’s a guide on resizing WordPress images to attain the appropriate image dimensions.

Another way of resizing images is by cropping. This removes parts of the original images and discards some pixels. Crop the image instead of dragging the corners to prevent distorting the image.

By resizing before compression, you’ll have already reduced the file size significantly. Compressing reduces it further until you attain the size you’re looking for. 

#3. Maintain the Original Aspect Ratio

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Illustration of image aspect ratio (License: CC BY-SA)

An image’s aspect ratio is the ratio of its width to height. It determines how an image will appear visually in different designs and is expressed as 1:1, 3:2, 16:9, etc.

When you resize images without maintaining the aspect ratio, they become distorted and appear stretched or squeezed. You don’t want this, as it causes visual and layout inconsistencies.

Most compression tools automatically maintain the aspect ratios when resizing images. If the one you’re using does not, consider migrating to one that prioritizes aspect ratio preservation. Alternatively, adjust the settings manually.

#4. Use Online Compression Tools

Look for a compression tool with batch-processing capabilities to compress images in bulk online. Popular tools like Adobe Photoshop and GIMP have user-friendly interfaces and bulk compression options.

Others, like ShortPixel Free Online Image Compressor, ImageOptim, and TinyPNG, are convenient, allowing you to compress images without installing software.

Compression tools often have adjustable settings, allowing you to control image quality. Depending on the quality you’re looking for, you can also choose between lossy and lossless compression.

Look for these features in an online compression tool to compress images in bulk.

  • Advanced compression algorithms for significant file size reduction without compromising quality
  • A user-friendly interface
  • Batch processing capabilities to compress multiple images simultaneously
  • Support for various image file formats like JPEG, PNG, and GIF
  • Adjustable compression settings
  • Preservation of metadata if it’s important
  • Backup creation 
  • Preview feature

Regardless of the tool used, the goal is to balance between reducing the file size and maintaining an acceptable visual quality.

#5. Adjust Compression Levels

This is the degree of compression you apply to an image. It determines the balance between reducing the file size and maintaining the image’s visual quality.

Higher compression levels result in smaller file sizes but reduced image quality. Conversely, lower levels preserve image quality but result in larger file sizes.

Compression tools allow you to adjust compression levels, usually expressed as a percentage or numbered scale. The right balance depends on the specific requirements of your project.

For instance, fast loading times are the goal for web and digital applications. Thus, slightly higher compression levels are required, emphasizing smaller file sizes.

Professional photography, on the other hand, prioritizes image quality and a lower compression level is preferable.

#6. Choose Between Lossy and Lossless Compression

Before you compress images in bulk, decide what image data to discard and what to preserve.

Lossy compression significantly reduces file size (up to 90% with Shortpixel) by eliminating image metadata.

Lossy Image Compression
Lossy Image Compression

The image quality is reduced but often invisible to the eye. This is acceptable where a minor quality loss is not a major issue, like in web images. JPEG employs lossy compression.

Lossless compression, characteristic of formats like GIF and PNG, retains all image data without loss in quality. This is important if your work requires preserving every detail, like in graphic design or professional photography.

Lossless image compression
Lossless Image Compression

Ultimately, your choice will depend on the importance of visual quality and how you intend to use the images. Your compression method should align with your project’s goals and requirements and deliver the expected user experience.

#7. Use High-Resolution Images

When compressing images in bulk, start with images of higher resolution than you need in the final product. Starting with a higher resolution allows more room for compression without sacrificing perceptible visual quality.

This technique is particularly beneficial when dealing with large batches of images. For example, web development, which requires maintaining clarity and smaller file sizes.

It caters to specific uses, such as responsive web design, which requires different image sizes for various devices.

However, be careful and strike the right balance. Excessively high-resolution images can still contribute to slow loading times and increased bandwidth usage.

#8. Create a Backup Before Compressing

Before you compress images in bulk, create a backup for the original images. This safeguards against potential data loss and unforeseen complications.

A backup is especially critical when compressing in bulk, where many image files are simultaneously altered. You can easily restore the original images if the compression doesn’t achieve what you want.

For example, if the compression was too aggressive and resulted in noticeable quality loss.

Some compression tools like ShortPixel create this backup automatically. If the tool you’re using does not, ensure you back up manually. You’ll have peace of mind without the fear of compromising your image quality, which can’t be reversed.

#9. Use WordPress Image Optimization Plugins

Compress images in bulk online using WordPress image optimization plugins.

Plugins like ShortPixel bulk-compress images from your media library with just one click. You can also set compression levels and automatically compress images upon upload.

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Shortpixel Image Optimizer WordPress Plugin

Other popular WordPress compression plugins are Imagify, EWWW Optimizer, and Smush.

Furthermore, these plugins come with other image optimization features like lazy loading and resizing, contributing to improved page loading times. 

Using these plugins is easy and efficient. Their user-friendly interfaces make them accessible even to people without technical knowledge.

Optimized images will give your site optimal loading speeds and a positive user experience.

Automatically Compress Images in Bulk with Shorpixel

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Shortpixel Image Optimizer

When dealing with a large number of images, it’s only sensible to compress them in bulk. You reduce their file sizes and make dealing with extensive image collections efficient.

But you need practical hacks and strategies to compress images in bulk online. You will achieve optimal compression by converting them to the appropriate formats, resizing before compressing, maintaining the aspect ratio, and using high-resolution images.

Compress images in bulk using the ShortPixel Image Compressor. This free online tool lets you choose between glossy, lossy, and lossless compression, create a backup, and even adjust compression levels.

Additionally, it’ll optimize and compress your images automatically.

Drop up to 50 image files or enter your URL and see what ShortPixel can do for your website.

Karol Carter
Karol Carter

Karol Carter is an experienced author and expert in various aspects of web development, online business, and digital marketing. Having worked with notable companies such as Automattic, Adobe, Ahrefs, Ecommerce Platforms, WebsiteSetup.org, WPAstra.com, CodeinWP, WinningWP, and Smashing Magazine, Karol has honed a wide range of skills and knowledge in the industry. From monetizing a blog to understanding the basics of SEO, designing websites, creating engaging content, and optimizing online visibility, Karol has covered it all.

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