Talk:PNG

message: The section "In contrast, when storing images that contain text, line art, or graphics – images with sharp transitions and large areas of solid color – the PNG format can compress image data more than JPEG can." could use a little clarification. I'm sure PNG can ALWAYS compress better than JPEG when the criteria is lossless reproduction of the original image (or something very close to it.) Does anybody have a reference where this information is from, and what criteria were used for this comparison?
80.212.191.68 (talk) 13:25, 26 December 2014 (UTC)
thread_title: PNG comparison

message: IE3 actually has a update available that allows it to support PNGs. I know this only because I remember applying it back in the 90s... 87.112.74.244 (talk) 13:49, 29 December 2007 (UTC)
replies: text: Pix or it didn't happen. 82.139.85.9 (talk) 02:46, 2 January 2008 (UTC)

text: I found two conflicting arguments for this on Microsoft's very own website: "Internet Explorer 3.0...PNG graphics" and "PNG output format requires Internet Explorer 4.0 or later", yet there is no mention of PNG in the Internet_Explorer_3 article. I'm not sure what to believe. Time to install Multiple IE. --Hm2k (talk) 10:02, 25 September 2008 (UTC)
thread_title:  Internet Explorer 3 

message: This page should contain a subsection in "Software support" called "Library support". 82.139.85.9 (talk) 02:46, 2 January 2008 (UTC)
thread_title:  Library support? 

message: 04-Feb-2008: The handling of PNG files on Wikipedia has involved many nightmares of changing problems with speed, access, display, and lockouts over the past year.  Although PNG files are typically 4x to 21x times slower than equivalent JPEG thumbnails, they have been used to display numerous photographs or paintings on Wikipedia.  There was even a massive effort to convert all small GIF or JPEG files (which showed a text label) into gargantuan PNG files, causing Wikipedia articles to become mostly PNG data and no longer primarily text in 2007. The massive size of PNG thumbnails can be seen by right-clicking on image properties in Wikimedia Commons, which formerly also worked on Wikipedia to show image width/height, file name, and file size. The right-click menu for PNG/SVG images was disabled on Wikipedia during late 2007 (but not on Wikimedia Commons), and it is no longer possible on Wikipedia to right-click open PNGs in a new window or display the image properties/sizes.  For a few days in November 2007, the right-click menu once again worked for Wikipedia PNG files, but in December 2007, the right-click menu for PNG images was disabled again.  As if that weren't bad enough, for people expecting to right-click open a PNG image in a new window, as of February 2008, attempting to stop the slow, massive download of gargantuan PNG files usually will lock-up a browser, until going offline. Formerly, all during 2007, a massive PNG file could be stopped by clicking the browser "STOP" button to quit the gargantuan download of the bloated PNG files, and resume viewing of a Wikipedia article.  However, in February 2008, the PNG download began forcing the browser window to continue the slow download of gargantuan PNG images by locking that browser window when the "STOP" button is clicked, and continuing a hacked download attempt, unless the browser is taken offline to release that locked window and resume viewing the page.  Not only are many Wikipedia files bloated with the mass of gargantuan PNG files, but once those PNG images begin the massive download, the browser window becomes jammed to prevent scrolling text.  However, by stopping a Wikipedia article soon after the text appears, the PNG images can be pre-empted, and the page can be scrolled to read the text (with blank images) or to just "Show Picture" for each JPEG or GIF image on the page.  To make matters even worse and worse, for a while, Wikipedia was forcing the text portion of each page to wait until the slow, massive download of gigantic PNG files was completed, BEFORE any part of a Wikipedia page would be displayed.  Of course, there was no Wikipedia announcement that these peculiar changes in spastic handling of the gargantuan PNG files would impact users in such bizarre and nightmarish ways.  Note that the problem is not the gigantic PNG files, but rather peculiar changes in the way Wikipedia displays PNG files, because on Wikimedia Commons, PNG files are always incredibly slow, massive downloads, but STOPPABLE mid-way, and the right-click has never been blocked to prevent viewing the massive sizes of PNG images, nor the browser locked or forced to display those gigantic PNG files on Wikimedia Commons.  The nightmare of unpredictable PNG image viewing, blocking, and browser lockups has only occurred on Wikipedia.  The use and handling of PNG images has made Wikipedia look like a very trashy and cumbersome website, as well as slowing response time for many thousands of Wikipedia users.  As usual, GIF and JPEG images incur no delays or lockouts of any kind.  At this point, I must advise: avoid using all PNG images on Wikipedia until the PNG-garbling has been resolved; GIF or JPEG images will still allow users to right-click open in a new window and can be stopped during display, without browser lockup. -Wikid77 (talk) 05:49, 4 February 2008 (UTC)
replies: text: This page is for discussing the article on PNG files. See Wikipedia:Bug reports for how to report problems with Wikipedia. --Zundark (talk) 08:41, 4 February 2008 (UTC)
thread_title: Wikipedia PNG nightmares

message: :"Apparently Adobe Fireworks is among the few tools that can produce semi transparent PNG8 files which degrade gracefully to single color transparency in the older IEs."
This seems a little unencyclopaedic. Also, is there a reference?  —Preceding unsigned comment added by Jordan Gray (talk • contribs) 02:34, 1 August 2008 (UTC)
thread_title:  Fireworks 

message: Please see the discussion at Talk:Image file formats#Naming_conventions_for_image_file_formats on naming conventions for articles on image file formats. Dcoetzee 00:47, 25 October 2008 (UTC)
thread_title:  Naming conventions for image file formats 

message: It would be better to use an image that does not contain anti-aliased fonts, as, for the viewer who does not know about aliasing, that will look a lot like JPG artifacts, thus lessening the message of the image. An image with crisp, sharp content would show the artifacts much clearer. 217.31.178.94 (talk) 10:32, 25 January 2009 (UTC)
replies: text: Feel free to replace the image with a better one. Plugwash (talk) 02:46, 29 March 2009 (UTC)
thread_title:  Comparison with JPG image 

message: Recently OptiPNG was considered for deletion, with no consensus emerging.  When that result was challenged at deletion review, the suggestion was made repeatedly that the best course of action would be to merge the article (or a summarized version of it) into this article.  I am bringing that suggestion here for discussion.  Another possibility to consider is a simple redirect, without a merge.  Thank you. Chick Bowen 00:49, 23 January 2010 (UTC)
replies: text: I agree that most of these optimization tools should be discussed together. If you read the paper by the author of OptiPNG, which is a very good source for technical info on the optimization issue, you'll see that the techniques employed by these programs are generally the same. Another good source is the chapter in Sayood's book cited in pngcrush#References. I'll add more technical details if others don't do it first. I don't have a lot of time to dedicate to this lately, mainly thanks to the threatened Great Purge of biographies that has to be dealt with at WT:COMPSCI and elsewhere. Pcap ping 06:52, 25 January 2010 (UTC)
replies: text: Thanks.  It's now been redirected by User:Stormie.  The history is still under the redirect if more is needed, including the refs that were in the old article. Chick Bowen 20:27, 25 January 2010 (UTC)
thread_title:  Merge from [[OptiPNG]] 

message: Are there any plans for PNG to support higher bit depths (like 16 bits per channel or Floating Point)? --70.167.58.6 (talk) 14:57, 5 October 2010 (UTC)
replies: text: 16 bpc are already there. — Ippopotamus (talk) 21:17, 5 October 2010 (UTC)
replies: text: 16 bpc was there from the start and any compliant decoder is supposed to be able to read it. I doubt floating point would be added in the forseable future firstly because adding a new format would break the idea that any png should be readable by any png decoder (which is a major advantage of png over say tiff) and secondly because I don't think there is demand for it outside of niche markets. Plugwash (talk) 16:41, 6 October 2010 (UTC)
replies: text:  I can't see what practical use there would be for floating-point RGB/greyscale values.  Moreover, floating point formats are platform-dependent.  Conversion between the platform's FP format and whichever the PNG group decides to use would be both a performance hit and potentially lossy.  This is already part of why we have flexible gamma, and why PNG uses floating points only in some ancillary chunks – where they are stored in a platform-neutral ASCII notation. — Smjg (talk) 11:23, 11 April 2011 (UTC)
thread_title:  Higher bit depths 

message: PNG Stereo - is this an official format or some hack? It has support in current programs (like this one), but two images side-by-side? That hardly seems well thought out. ▫ JohnnyMrNinja 02:09, 3 February 2011 (UTC)
replies: text: I'm puzzled by it.  Why should a file format specifically designed to hold two images have a concept of them being "encoded side-by-side"?  If it's a format that structurally holds two images, they would not have any physical position relative to each other.  If it just holds them side by side as if they're one image, it would defeat the whole point of having a separate format.  Besides, the official format for storing multiple images in one file is MNG, further suggesting to me that PNG Stereo is a hack.  And a totally pointless one at that - PNG is perfectly capable of holding a stereogram as two images side by side.  It even has a standard chunk to indicate this. -- Smjg (talk) 14:57, 18 February 2011 (UTC)
replies: text:  Looking at Nvidia 3D Stereo documentation, it appears that a PNS file is just a standard PNG file, and the claim that it's a separate format with a separate filename extension is a marketing gimmick.  Moreover, it isn't clear whether a PNS is just a standard PNG stereogram (i.e. has the right-hand image aligned on an 8-pixel boundary and a sTER chunk) or a divergent way of doing the same thing. — Smjg (talk) 20:15, 10 April 2011 (UTC)

text:  At the moment, there's an AfD for PNS and the very similar JPEG Stereo.  Please share your thoughts.  If it gets replaced by a brief mention here, I can see that it needn't be more than one or two sentences. — Smjg (talk) 11:12, 11 April 2011 (UTC)
thread_title:  PNG Stereo 

message: Should there be an example of an animated png, such as: http://www.libpng.org/pub/png/img_png/adam7gif.gif  ?  I profess near complete ignorance on the subject, and so cannot be bold here, but it seemed like a good idea.Slarty2 (talk) 20:51, 11 April 2011 (UTC)
replies: text: Wouldn't it make more sense to put the example in Multiple-image Network Graphics?  And the specific example you suggest is an animated GIF, not a MNG -- Elphion (talk) 21:05, 11 April 2011 (UTC)
replies: text:  PNG and MNG are distinct formats.  There's no such thing officially as an animated PNG.  Moreover, MNG isn't widely supported by web browsers, though that doesn't mean we can't add an example there just in case (just as we've been using Ogg for audio since before browsers supported it).  Anyway, you might be better off taking this discussion to Talk:Multiple-image Network Graphics. — Smjg (talk) 13:31, 31 October 2011 (UTC)
thread_title:  .mng example? 

message: I wanted to update several maps here on wikipedia, which were made in this format. I think there should be a link somewhere on the article page about how to handle it in wikipeida. Is there any easy way i can update a map? — Preceding unsigned comment added by Ilya-42 (talk • contribs) 13:51, 19 July 2011‎ (UTC)
: The procedure for updating images on WP doesn't depend on the file format.  In a nutshell: Save the full resolution image from your browser, then edit it in your favourite graphics app, then when you're done, use the "Upload a new version of this file" link near the bottom of the image description page. — Smjg (talk) 13:06, 31 October 2011 (UTC)
thread_title:  How to use this shit on wikipedia? 

message: Perhaps a link to the disambiguation page would be appropriate since png autodirects here.  — Preceding unsigned comment added by 132.181.61.215 (talk) 01:20, 20 September 2011 (UTC)
replies: text: PNG is the disambiguation page.  I've changed png to redirect there. -- Elphion (talk) 03:35, 20 September 2011 (UTC)

text: (added) I have no axe to grind about whether alternatives to "PNG" are mentioned here via hatnote or whether "png" (l.c.) goes to PNG, but clearly people searching for some capitalization variant of "PNG" need to get some indication that there are alternative targets. -- Elphion (talk) 03:40, 20 September 2011 (UTC)
thread_title:  Papua New Guinea 

message: A comparison to BMP should be added.50.103.230.83 (talk) 14:31, 30 January 2012 (UTC)
thread_title:  Comparison to other file formats  

message: has twice edited the lead to insist that the compression method used by PNG is not lossless.  This is nonsense, and completely contradicts the point of PNG.  PNG uses DEFLATE, a well-known algorithm that is in fact lossless (it is commonly used in zip programs for text files as well).  The added material about MS Paint may or may not be true (it would require an authoritative source), but even if true, it does not address the losslessness of DEFLATE or PNG, but rather flaws in how MS Paint handles images.  (And in any event, it does not belong in the lead.) -- Elphion (talk) 12:44, 30 September 2012 (UTC)
thread_title:  Lossless compression 

message: It states the JPEG 2000 can contain EXIF data, but if you go to the EXIF page on Wikipedia it says that it's not supported with JPEG 2000. Which is it?  — Preceding unsigned comment added by 67.141.250.181 (talk) 22:41, 17 December 2012 (UTC)
thread_title:  EXIF & JPEG 2000 

message: Which computer programs can an image be pasted as transparent into? Which of them allow a multicolored transparent background to paste as transparent? Which programs can support pixels of an image, such as :File:Light cone.svg being pasted as partly transparent? Blackbombchu (talk) 21:03, 5 April 2014 (UTC)
replies: text: Check out Alpha channel.  Enumerating applications that can display alpha channels correctly is beyond the scope of this article. -- Elphion (talk) 22:11, 6 April 2014 (UTC)
thread_title:  More to add about transparency 

message: It is worth linking to PNG tools overview as it seems to cover pretty much all the PNG tools at the time of writing (April 2014). One of the tools mentioned on that page is could also be added here - pngwolf because it uses genetic algorithms to try and search for the best filters (pngwolf can even be seen helping zopfli). 
87.112.13.231 (talk) 17:01, 26 April 2014 (UTC)
thread_title:  PNG tool additions 

message: Should the article include anything related to vulnerabilities, such as PNG Decompression Bomb? • Sbmeirow • Talk • 05:57, 26 November 2015 (UTC)
thread_title:  PNG Decompression Bomb Vulnerabilities 

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thread_title:  External links modified 

message: The provided contents of a minimal PNG containing a single red pixel does not explain the purpose of each included byte/parameter, nor what the compressed IDAT data decompresses to. For example, the purpose of the bytes 0x08 0xD7 in IDAT does not appear to be stated anywhere on the page. In particular, I attempted to decompress the data in IDAT by hand using the static Huffman code, and extracted the values 0x00 0xFF 0x00 0x00, which makes sense, corresponding to one line with filter type 0 (none), and one literal red pixel (0xFF 0x00 0x00). This decoded data was terminated by the end-of-block signal; however, there were still four more bytes remaining in the content of the IDAT chunk before the CRC with the values 0x03 0x01 0x01 0x00. What are these bytes for?
2601:182:280:C0F0:D9BB:9350:ABFD:196E (talk) 19:22, 18 August 2021 (UTC)
thread_title: Minimal PNG Explanation