In this post, we will talk about the best free image compressor & optimizer software for Windows 11/10. Image compression is handy to reduce the size of images (say from 1 MB to 300 KB) which further helps in saving the disk space. It can also come in handy when you have to share your image collection on social networks or with someone. You can generate a copy of the original images with compressed size and use it anywhere. The width and height of the image are not changed, only the file size is decreased by reducing the number of colors or image quality. The output images look exactly the same as input images. You can open the compressed images in any photo viewer apps or software and you won’t notice any change.

Image compressor & optimizer software for Windows 11/10

We have covered five free image optimizer software. Before using any of these software, you should also make a backup of your original images, just in case:

Mass Image Compressor
Imagine
Caesium
Romeolight PNGmicro
imagemin-app.

1] Mass Image Compressor

Mass Image Compressor is open-source software and it lets you batch compress image files. You can add a folder containing JPG, PNG, and RAW format images and compress them. There is a slider available to set the image quality. This software also comes with other options like compressing images only if the file size is greater than the defined size, preview output images within the interface, setting output width or keeping the height & width the same as original, and saving images as PNG or JPEG or in the original format. If you are converting RAW images, then the output is automatically set to JPEG which can’t be changed.

Download this software here. On its interface, use the Browse icon to add the image folder. A Compress Images of All Child Directories option is also there to compress images present in sub-folders but that option overwrites the original images present in those sub-folders. So, you should uncheck this option.

After that, use the slider to set the image quality. To keep the size (height n width) of output images the same as the original, select New Dimension in % option, and set its slider to 100%. Continue the steps and set the output folder using the available button.

When everything is done, press Compress All button. It will compress images one by one and store it in the output folder. You can also preview any output image on the bottom part and also use zoom in and zoom out options to preview the image. For each image, the preview section also shows the before and after size and size reduction in percentage which is a good feature.

2] Imagine

Imagine is a cross-platform, portable, and open-source image compressor software. This software comes with a modern interface that is clutter-free. It also brings bulk image compression feature. The option that I like the most is you can set quality size for each individual image separately. Also, you can see the large thumbnail size preview of input images and save all compressed images in one shot or save images one by one.

You can download it here. On its interface, you can either drag n drop images (JPG and PNG) or use Add button. After that, it will show the preview of input images and automatically compress those images with default settings. For each image, there is a separate slider available to compress it. Use those sliders to compress images. If you want, you can also change the default compression option using the Settings icon available on the top right part.

To save the compressed images, hover the mouse cursor on Save button. It will show three options: Save and overwrite, Save with new name auto, and Export to. You should use the third option to generate a separate copy of compressed images.

Read: Best free online tools to compress images.

3] Caesium

Caesium is another open-source image compressor software that can reduce image size up to 90%. It supports batch compression for JPG, PNG, and BMP format images. You can set quality level for JPG images, but for PNG and BMP images, it automatically adjusts quality level. It also lets you select if you want to keep or remove EXIF data for compressed images. You can do that by accessing the Compression section under Settings menu of this software.

To compress images, use Add Pictures button or File menu. After that, it will show the list of input images. That list also shows other information like new and original size of images, image quality, path, etc. On the bottom part, you can use options to set the output folder, image quality (for JPG), resize output images or keep the original size, and more. Use options and then press Compress! button.

All the compressed images are stored in the folder set by you. If you want, you can also preview the original and compressed images on the right section of its interface.

4] Romeolight PNGmicro

Romeolight PNGmicro can bulk compress PNG images. It comes with a dark-themed interface where you can see image name, new size and optimized size, and path of original and compressed images. You can also use Settings icon (available on the top right section) to set compression factor or quality, output folder, enable interlaced option to compress and save the output in multiple passes, add transparency effect to compressed images, etc.

This software can be downloaded from here. It is available in portable and installer versions. Download the one that fits your requirement. After that, you can drop images on its interface or use Add Files button.

When images are added, access Settings to set options as per the needs. Finally, press Optimize button just next to the Add Files button to compress and save output images.

5] imagemin-app

imagemin-app is the simplest image compressor software in this post. This open-source and portable software doesn’t with any Settings, quality factor, or other options. There will be a blank interface in front of you where you can add PNG images in bulk for compression.

Download it here. When you have opened its interface, either drop a folder containing PNG images or select images and drop them. After that, it will automatically process those images. When the processing is done, it creates an optimized name folder in the same location where input images are present and stores all the compressed PNG images in that folder.

If you are looking for similar free image optimization software, you can also check out:

I hope these free image compressor and optimizer software will help you in optimizing images with ease. I like the Imagine software as it provides separate sliders to set quality for each image. But, other software are also good at providing the expected output.