Martin JørgensenWith Caesium, you can compress and resize your images so they’re easier to share online. Download the software free for Windows and Mac!
If you’ve just imported all your photos from your camera and want to upload them online (for example to your blog or Google Drive), storage space can quickly become an issue. With the Windows and Mac app Caesium, you can quickly and easily compress and resize your images so they take up far less space.
On this page, you’ll find everything you need to know about Caesium: how it works, how to use it, and a quick look at its key features. You can also read what we think of Caesium after a short test on Windows.
Remember to keep your original files
Before you start using Caesium, a quick reminder: it’s always a good idea to keep your original image files so you can return to them later. Only delete them if you’re sure you’ll never need those images again.
When you compress images with software like Caesium, image quality will decrease. That’s obvious, but still worth noting. If you’re compressing a batch of photos to upload smaller versions to your website or similar, it’s smart to keep the originals somewhere offline on your computer.
Installation
We tested the Windows version of Caesium on a PC with Windows 11, and the installation went smoothly. Just choose where to install the program and whether you want a desktop shortcut. At the end, the installer asked us to restart the computer to complete the setup.
If you use Windows, there are actually two different builds you can download. There’s the standard installer, and there’s also a portable version of Caesium. If you choose the latter, you don’t install anything at all—it’s a ZIP archive you download and extract anywhere on your PC.
The benefit of portable apps is that they run in their own self-contained folder. You can, for example, copy the program folder to a USB drive and run it on other computers directly from the USB drive. Handy!
Interface
When you open Caesium for the first time, you’ll notice the interface is clean and straightforward. It won’t take long to figure out how to use it.
The first step is to import the images you want to compress or resize. Click “Add files” or “Add folder” at the top, or simply drag and drop files into Caesium to batch-process many files at once.
Once the images are added, decide what you want to do with them. On the right side, you can adjust the compression and resizing settings. We describe these steps further down. Finally, click the “Output” tab to tweak export options before Caesium processes your images.
Compression
To compress your images, use the options on the right under the “Compression” tab. Compression reduces file size but also lowers image quality.
You can set quality levels for JPEG, PNG, and WebP, or choose lossless if you don’t want to compromise quality. You can also choose whether to keep or strip metadata.
Resizing
To change your images’ resolution, open the “Resize” tab. Resizing adjusts width and height. For example, if an image is 800 by 600 pixels, halving the resolution results in a 400 by 300 pixel image.
When you resize to a lower resolution, files get smaller too. If your images are too large, you can both compress and resize them—or do just one of the two. It depends on how you plan to use the final images.
We’re a bit disappointed that Caesium can’t add watermarks. Not everyone needs this, but if you’re uploading images to your blog, it can sometimes be helpful to protect them with a watermark. That isn’t possible in Caesium.
Conclusion
In short, we really like Caesium. The interface is simple, the app is extremely easy to use, and we encountered no issues while testing the Windows version on a PC with Windows 11.
The only notable downside in our view is the lack of a watermark feature. If you don’t need that functionality, we can highly recommend giving Caesium a try.
Remember, it only makes sense to compress and resize your images when necessary, because the process reduces quality. It’s always best to store your photos in the highest quality possible. Still, there are many situations where smaller images are useful—and Caesium is a great way to get them.
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