JPGExtra – Sample Icon-sized JPG File
When an image is made smaller, many of the unseen "extras" within the resulting JPG file can still be just as large, constituting a greater percentage of waste. Typical icon-sized JPG files will benefit the most from optimization by JPGExtra.
Sample Icon-sized JPG File
This is a fairly typical icon-sized photographic image that one might see on any website:
- File name: BushOrchids80x80.jpe
- Image size: 80 x 80 pixels
- File size: 19,253 bytes
Icon-sized images are often used as a preview to a larger image, although occasionally small images are used on their own. This icon started out as a photo taken with a digital camera, which was then cropped and resized with Adobe Photoshop.
The image itself may be small, but let's peek inside the JPG file...
Revealing What's Inside
Decoding the innards of the icon-sized JPG file reveals almost the identical amount of "extras" (or "metadata") as existed in the larger image:
- JFIF Header
- Exif data
- Thumbnail(s) (both smaller)
- Photoshop data
- Adobe XAP data
- ICC profile
- Adobe data
- Main image (smaller)
Whereas the larger image contained 44% of "extras", this icon-sized JPG file contains a massive 79% of waste. I've seen some with more than 99%!
The sizes of the "blocks" in the above image represent their relative sizes within the file, with the important sections colored with green borders and the "extras" colored with yellow borders. It's easy to see that more than 3/4 of the file is waste.