What does resizing to 25% mean?
It scales both width and height to 25% of the original. A 2000×1000 image becomes 500×250. The aspect ratio is always preserved.
Will this reduce file size?
Yes. Reducing to 25% decreases pixel count by 75%, which significantly reduces file size. Exact savings depend on the format and content.
Can I resize back to 100% later?
You can enlarge it back, but quality will be lost since pixels were removed. Always keep your original file as a backup before resizing down.