Compressing vs resizing
Compression changes how image data is encoded, while resizing changes the number of pixels. Resizing a 4000-pixel photo to the dimensions actually needed by a website or email often saves more space than lowering quality alone.
Choosing JPG, PNG, or WebP
JPG is usually efficient for photographs but cannot keep transparency. PNG preserves sharp graphics and transparency, although photographic files can be larger. WebP often provides a useful balance of image quality and file size in modern browsers.
Practical examples
- Reduce camera photos before attaching them to email.
- Resize product images to a consistent website width.
- Convert PNG screenshots to WebP when a smaller web asset is needed.
- Prepare several images for an online form in one batch.
Privacy and metadata
All processing happens in your browser on this device. Images are not uploaded to OfficeKits servers. Re-encoding removes embedded metadata such as camera and location details in this version.
Troubleshooting
A result can be larger when the chosen format is inefficient for that image, the output dimensions increase, or the quality setting is high. Converting a transparent image to JPG places transparent pixels on a white background. Very large images may exceed the memory available to your browser.
Frequently asked questions
Does image compression reduce dimensions?
Not unless you select a resizing option. Compression and dimensions can be controlled together or independently.
Why does PNG ignore the quality slider?
Browser PNG encoding does not expose a dependable lossy quality setting. Resize the image or choose JPG or WebP when a smaller result is more important.
What happens to transparent pixels when I choose JPG?
JPG has no transparency channel, so transparent areas are placed on a white background.
Are my images uploaded?
No. Decoding, resizing, encoding, and ZIP creation happen locally in your browser.
Why can an optimized file become larger?
The target format, dimensions, and quality determine the result. Try a smaller dimension, a lower quality, or WebP for photographic content.