Ian's Software Site - JPGExtra Program - Optimize JPG files with no loss of image quality by cleanly removing extras

Ian's Software Site - Minimalist software programs that are tiny yet very powerful

JPGExtra Program

Optimize JPG files with no loss of image quality by cleanly removing "extras", those hidden bits of information that are typically embedded in files by digital cameras and image editing software. Removing those extras can easily save 50% or more, resulting in faster page load times, reduced storage requirements and lower bandwidth costs.

NEW RELEASE! Version 2 has just been publicly released!

Hidden Extras in JPG Files

JPG File Headers

Thumbnail Image

Digital Camera Info

JPG File Headers

ICC Color Profile

Image Editor Data

Comment / Credits

JPG File Headers

Some Other Stuff

JPG File Headers

JPG Image Data

Even More Stuff

Typical JPG File:
At left is the breakdown of a typical JPG file. The various green and blue sections are all that's actually needed to display the image. The various yellow sections are all "extras", which are ignored by web browsers and JPG image viewing programs.

However, those yellow sections still take up disk space and, more importantly, consume bandwidth when they are downloaded, even though they are not "needed". The result is that JPG files can easily take twice as long to download and display as they should.

JPG File Headers

JPG Image Data

Optimized JPG File:
Removing all the yellow "extras" and combining some of the green sections whilst leaving the blue section intact results in a much smaller JPG file, yet the resulting image will look identical to the original image because the JPG image data is completely unchanged.

JPGExtra To The Rescue:
JPGExtra optimizes JPG files by cleanly removing all the hidden extras, reducing their overhead to an absolute minimum. The optimized JPG files download more quickly -
- which allows the browser to show the images sooner -
- which results in the web pages displaying faster -
- which in turn speeds up the whole web site and cuts bandwidth costs!

Best of all, JPGExtra removes those extras without any re-compression of the JPG Image Data, which means that there will be no further loss of image quality.

JPG Files With Or Without Extras
What's The Difference? Those hidden extras can make a huge difference to the size of the JPG file whilst making no difference to the image. Here's some real-world examples:
Original JPG File = 29,375 bytes This is a fairly typical JPG file. It started as a high-resolution photo from a 5-Megapixel digital camera. Using Photoshop, the image was resized to fit onto this web page and saved as a JPG file with a modest "quality" setting.	Optimized JPG File = 11,415 bytes Optimized file after processing with JPGExtra, which removed 17,960 bytes of "extras". Despite eliminating 61% of the JPG file, the picture looks absolutely identical because the JPG image data is completely unchanged.
Original JPG File = 16,603 bytes Web sites often have many small "preview" images, especially for product images on catalogues or e-commerce sites.	Optimized JPG File = 2,102 bytes This time JPGExtra saved 14,501 bytes, a similar overall saving as above but a much higher percentage (87%).
Original JPG File = 26,651 bytes To reduce extras, a savvy Photoshop user may un-tick the options for "Thumbnail" and "ICC Profile" when saving a JPG file.	Optimized JPG File = 19,613 bytes Although fewer "extras" have been stored in this JPG file by Photoshop, JPGExtra still managed to remove 7,038 bytes (26%).
Original JPG File = 10,516 bytes This small image has also been saved from Photoshop with the "Thumbnail" and "ICC Profile" options un-ticked.	Optimized JPG File = 3,504 bytes This time JPGExtra saved 7,012 bytes, a similar overall saving as above but a much higher percentage (67%).
See For Yourself: To demonstrate this yourself, use the current page as a simple test. Position the page so that you can see some of the above images. Clear the cache on your web browser (eg. "Temporary Internet Files"), then reload this page, usually by pressing [F5]. You should notice that the original images on the left side took longer to display than the optimized images on the right side. This was not done through any browser trickery (like "preloading" files), it's simply that the JPGs on the left were still busily downloading those hidden "extras" whilst those on the right immediately started displaying the images.

See also the JPG Technical Info page for a more detailed explanation of the types of extras, where they come from, how much space they occupy, and any possible privacy implications they may expose.

Conclusion

I've found that almost all web sites have JPG files containing hidden extras, ranging from a few bytes to tens of thousands of bytes per file. Large numbers of such files on a web site can create a significant impact:

Increased disk space requirements
Higher bandwidth costs and higher peak bandwidth
Longer page load times, which affects web rankings
More frustration for site visitors

Anyone serious about web site optimization will understand that it pays to strip all excess from JPG files to make them as lean and fast as possible. Luckily, there's a quick, simple solution for optimizing JPG files: JPGExtra

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