jStrip 1.31

©1999 David Crowell

This version of jStrip is free. I am planning on releasing a shareware version with more features, so stay tuned.

You may distribute this software freely by any means as long as there is no charge for it (other than reasonable media charge) and you must distribute the entire unaltered archive. By using this software, you agree to not hold the author, David Crowell, liable for any damage to your data or computer.

What is jStrip?

JPEG files generally contain 'extra' data that isn't used by web browsers or most image viewers. This extra data takes time to download when viewing a web page, and takes additional hard drive space. Most of the time it is safe to remove this extra data.

jStrip removes this extra data. It does not have to recompress the image data, so there is no image quality loss. It will remove thumbnail data that is not usually seen. It will optionally remove comments, and APPx markers including the JFIF marker.

Installation

jStrip requires the Visual Basic 5 runtime files in order to run. They are available from my web page. If you run jStrip and get an error about a missing file, MSVBVM50.DLL, then you need the runtime files.

To install jStrip, simply copy all of the files in this archive into a new folder, and create a shortcut to jstrip.exe somewhere handy.

How to use jStrip

Select Edit | Options from the menu. Choose your options from the available choices. The default options are a good starting point. You only have to do this once, as they will be saved to the regsistry.

Navigate to the folder that contains the files you wish to process. Choose the files you would like to process. You can use the A N I buttons above the file list to select all, select none, or invert your selection, respectively.

Click Start to begin the process. When the process completes you will see a short summary. If you selected the 'Write to log' option there will be a logfile in the folder with the processed files. Look for JSLOG.TXT It contains details about each file. Any files that jStrip is unable to process will remain unchanged. Any files jStrip is unable to save any space from will remain unchanged.

Options

Process Read Only Files

If this option is checked, jStrip will attempt to clear the read-only attribute of the file to be re-written.

Keep Original File Date

If this option is checked, jStrip will not modify the 'last modified' date of the file when re-writing it.

Write log to JSLOG.TXT

If checked, jStrip will write a logfile in the affected folder, listing the details of each file processed.

Remove APPx markers

The JPEG standard defines an application-specific marker known as an APPx marker (where x can be from 0 to 15) The most common use for these is the APP0 marker which usually marks a JFIF compliant JPEG. Photoshop adds it's own APPx markers to store Photoshop specific information.

jStrip (even with this option unchecked) will remove most of these markers. It will only leave the APP0 (JFIF) marker, and the APP14 (which is used by Photoshop for CMYK encoded files).

Checking this option will force remove jStrip to remove all APPx markers. Checking this can damage CMYK encoded JPEG files. I generally don't recommend using this option.

Remove Comments

Checking this option will remove embedded comments from the JPEG file. You may leave it unchecked to leave any existing comments. Comments are simply text strings embedded within the file that can contain 'This file created with XXXXXXXX' or something like that.

Versions

Version 1.31 released November 16, 1999

  • Version 1.3 would always remove comments, this is now fixed. (I really goofed, and nobody caught it)
  • Two *very small* performance enhancements.
  • Source code is no longer available, sorry.

Version 1.3 released July 1, 1999

  • Log listings will not be generated for JPEG files that no additional data can be removed from
  • Fixed bug causing 4-color CMYK JPEGs to be damaged. (rare file type)
  • Fixed minor bug causing jStrip being unable to process certain files. (rare also)
  • I've enhanced the speed of the stripping process a bit
  • Enhanced the user-interface a bit.
  • Option to remove all APPx markers.
  • Removing comments from a JPEG is now optional.
  • Window postion and options are now stored in the registry.
  • I no longer include the source code with jStrip, but most of it is yours if you ask.
  • Actually have a nice looking icon now :)

Version 1.2 released December 20, 1998

  • Option to overwrite read-only files added.
  • Option to keep original modified date added.
  • Option to not write log added.
  • Mostly complete re-write.
  • Fixed minor bug which caused all files to be re-written, even if no changes were made.

Version 1.0 released October 16, 1998

  • Original release.

Credits

  • James Cadden found the CMYK bug, I never would have on my own.
  • Joseph Maddison bugged me quite a bit to get another version out. I guess I owe something to him too. :)
  • Antoine Fanis has been helpful in making this file easier to understand.
  • The section of code in jStrip that provides the means to save settings to the registry was written by Karl E. Petersen. Thanks Karl.
  • Thanks to DavidT for giving me the idea to reset read-only files.
  • Thanks to John R. Onda for the idea to set set file date & time back to the original.
  • Thanks to Scott Fulkerson and Piero Desopo. They both wanted a quick way to select all files. Both the 'All' button, and ctrl-A work now.
  • Thanks to Steve "Ice Cube" Lombardi. He suggested an option to turn off logging.
  • I really want to thank VBNet. I located the information on how to change a file's last modified date from there.

What's coming?

Doing entire folder trees will be in version 2.0. I've already created a command-line version that does this along with creating backups, and displaying comments, but this command-line version is not available to the general public. I'm using it as a testbed for new code, and Joseph Maddison has been helping with testing.

The shareware version will have many new features, several useful add-on programs, and an actual setup program. I'm guessing the price will be $15 for a single user license.

This freeware version will continue to be available even after the shareware version is released.

Comments welcome

Please let me know what you think of jStrip. I'm open to suggestions on improving it.
Email: dave@davidcrowell.com
Web: www.davidcrowell.com