PngOptimizer (Freeware)

[XnTriq]

I've been using v1.8 for years now. It's the perfect companion to XnView. The command-line version can be integrated into XnView's toolbar.

• Clean your PNG files of useless or wrong information.
• Make your PNG files smaller.
• Convert into PNG other lossless image formats (BMP, GIF, TGA).
• Create PNG screenshots and make them easily available.
• Perform all those tasks in the simpliest and most productive way.

PngOptimizer 2.0 (25/Apr/2011)

• new: support for APNG for both optimization and conversion (animated GIFs)
• new: x64 version
• new: PNG options moved to their own dialog window
• new: option to ignore animated GIFs
• new: option to keep original file date and time
• new: option to force background color (bkGD chunk)
• new: option to keep or force textual information (tEXt chunk)
• new: always on top option for the main window in the contextual menu
• new: suggested screenshot filename now keeps leading "0" for file number (file 001.png, file 002.png...)
• new: suggested screenshot filename now accepts "-" as a number separator (file-01.png file-02.png...)

• change: AvoidGreyWithSimpleTransparency is now disabled by default (was for IE6 compatibility)
• change: keyboard shortcut to clear the list is slightly less complicated: Ctrl+Delete instead of Ctrl+Shift+Delete

• misc: better results with some cases of indexed color images
• misc: updated ZLib 1.2.3 to 1.2.5 (compression library)

• fixed: bad % reported for large files
• fixed: hangs at startup when loading an empty configuration file (PngOptimizer.ini)
• fixed: could not load GIFs containing non-Netscape application extensions blocks (like XMP data from Photoshop CS)
• fixed: could not load GIFs with a compressed block ending with a terminator instead of an end-of-information code

[eL_PuSHeR]

Ken Silverman's PNGOut or Cosmin Truta's OptiPNG are better in my humble opinion. I didn't try the command-line version, but the GUI one is really awful.

[thibaud]

Ken Silverman's PNGOut or Cosmin Truta's OptiPNG are better in my humble opinion. I didn't try the command-line version, but the GUI one is really awful.

I have to disagree, here is a short comparaison I did (win 7 x64|i7 980x|24GB RAM)

A.PRICE:

• PngOptimizer: Open source (GNU)
• PNGOut: 15$ to 30$
• OptiPng: Open source.(zlib/libpng)

B.COMPATIBILITY:

• PngOptimizer: x86 & X64 | Reads: PNG, GIF, BMP, TGA.
• PNGOut: x86 only | Reads: PNG, GIF, TIFF, BMP, JPG.
• OptiPng: x86 only | Reads: PNG, GIF, BMP, PNM, TIFF.

C.PERFORMANCE (55 PNG files processed | 487KB) :

• PngOptimizer: 2.5 sec | 342KB (70,4% of original)
• PNGOut: 24 sec | 372KB (76,4% of original)
• OptiPng: 4 Minutes 22 sec | 476KB (97,9% of original)

I believe you may have judge PngOptimizer a bit too quickly.
Focusing your judgement on a gui (which btw is near perfect | how can you find a design flaw in a bare naked window ?) can be seriously misleading.

[Drahken]

Your price comparison isn't entirely accurate. There is indeed a commercial GUI version of PNGout (I didn't check the price, but I suspect your 15~30 is correct). However, the commandline version is free, plus there is a free GUI available for it ( http://pnggauntlet.com/ ), plus (more importantly) it is available as a free plugin for xnview.

...speaking of which, xnview's PNG export functions are quite effective & infinitely faster than PNGout (I haven't tried the other 2 progs), just experiment with the different filters for better results.

[eL_PuSHeR]

One thing I didn't like is that PngOptimizer removed the resolution tag from the PNG processed. Maybe the command-line version has some option to keep some tags.

And yeah, I admit PNGOut can be quite slow.

[DOS386]

Ken Silverman's PNGOut or Cosmin Truta's OptiPNG are better in my humble opinion. I didn't try the command-line version, but the GUI one is really awful.

Minimal test: PngOptimizer beats OPTIPNG but inferior to PNGOUT (16 col's).

PngOptimizer (CL) flaws:

- no progress indicator
- very little info

PngOptimizer benefits:

- can also optimize APNG reportedly (untested)

x86 only

doesn't it work for you ???

[*]PngOptimizer: 2.5 sec | 342KB (70,4% of original)
[*]PNGOut: 24 sec | 372KB (76,4% of original)
[*]OptiPng: 4 Minutes 22 sec | 476KB (97,9% of original) [/list]

Please submit some PNG exposing PngOptimizer to beat PNGOUT.

[DOS386]

I wrote:

Minimal test: PngOptimizer beats OPTIPNG

far not always ...

[*]PngOptimizer: 2.5 sec | 342KB (70,4% of original)
[*]PNGOut: 24 sec | 372KB (76,4% of original)
[*]OptiPng: 4 Minutes 22 sec | 476KB (97,9% of original) [/list]

Most likely you swapped the results from PngOptimizer and PNGOut

Code: Select all

921'654 Original BMP 24bpp

after LIBPNG/PO/PNGOUT/OP only:

433'833 LIBPNG -9
433'188 PO
430'300 PNGOUT (rare missguess "/f5")
409'796 OP -o7 (brutes out "/f1")
392'538 PNGOUT /f1 | !!! WINNER !!!

after DEFLOPT additionally:

432'810 LIBPNG -9
432'810 PO         | !!! IDENTICAL to LIBPNG -9 above !!!
430'282 PNGOUT (rare missguess "/f5")
408'637 OP -o7 (brutes out "/f1")
392'525 PNGOUT /f1 | !!! WINNER !!!

To sum it up, PngOptimizer seems to be far inferior to PNGOUT and still a bit inferior to OPTIPNG.

About PngOptimizer's AGIF->APNG conversions, the output is good is some cases but bad in other cases.

[thibaud]

Most likely you swapped the results from PngOptimizer and PNGOut

I didn't swap any results!
please note that my test was run not with one particular BMP but with 55 png (a good number of them had transparency).
also, you don't seem to provide processing time, which I believe is quite relevant too.
btw, I never stated Pngoptimizer "was far superior" or "beated" anything, I try to avoid to make bold statement like theses. I was merely trying to provide numbers.

[XnTriq]

PngOptimizer v2.1 (09/Jun/2012):

• new: option to keep or force pixel physical dimensions (pHYs chunk)
• new: better compatibility for old Windows versions (NT based)
• new: Windows Seven taskbar icon now shows progression of an optimization
• new: better automatic dialogs placement when near screen borders, near taskbar or with multiple monitors
• new: the list is now scrollable with the keyboard
• new: "Done" written at the end of multiple files optimization
• new: screenshot directory dialog can be resized

PngOptimizer v2.2 (09/Sep/2012):

• new: support of the ".apng" file extension
• fixed: only lower case file extensions were managed. The extension case is not relevant anymore.

[DOS386]

XnTriq wrote (1/2 year after the release) :

PngOptimizer v2.2 (09/Sep/2012)

Commandline version still exists ... changes are very minor, no engine improvements.

[XnTriq]

PngOptimizer v2.3 ( 29/May/2013)

• new: multithreaded optimization for faster processing on multicore CPUs
• new: better optimization in some cases of greyscale images
• misc: updated ZLib 1.2.5 to 1.2.7 (compression library)

[DOS386]

The changes seem very minor again.

• new: multithreaded optimization for faster processing on multi
• new: better optimization in some cases of greyscale images
• misc: updated ZLib 1.2.5 to 1.2.7 (compression library)

Why not use zopfli ? Then the author could finally beat PNGOUT and OPTIPNG

[thibaud]

The changes seem very minor again.

• new: multithreaded optimization for faster processing on multi
• new: better optimization in some cases of greyscale images
• misc: updated ZLib 1.2.5 to 1.2.7 (compression library)

Why not use zopfli ? Then the author could finally beat PNGOUT and OPTIPNG

I suppose because performance isn't solely related to the compression (size reduction) ratio.
Processing time is an important factor too.
100x slower ! for a 5% gain definitively isn't an overall improvement in my book.

[XnTriq]

PngOptimizer v2.4 (18/May/2014)

• misc: updated source code for Visual Studio 2012
• misc: welcome message is centered and appears only when the log window is empty
• fixed: some errors found with VS2012 static analysis tool
• fixed: small UI problem in the screenshots dialog
• change: removed batch summary for single file

PngOptimizer v2.4.1 (25/May/2014)

• fixed: Windows XP compatibility for 32 bits build

PngOptimizer v2.4.2 (08/Jun/2014)

• fixed: x64 build failed to open dialog boxes on Windows 8

[XnTriq]

PngOptimizer v2.4.3 (24/Jul/2016)

• misc: updated file structure for git first commit

PngOptimizer v2.5 (09/Ovt/2016)

• misc: update code for GTK+ version
• misc: reorganize Windows code for multiplatform support
• misc: update distrib script to create a .deb package