Jim Lawrence (AccessD)
accessd at shaw.ca
Mon Apr 26 19:55:53 CDT 2004
I have found that GIF and PNG files are virtually identical in compression size. I used Fireworks to compress files and had little difference in size or quality but...If you have to use screen shots, that have many tonal colours GIF/PNG files are not the correct format. The method that I use rendering large graphics objects smaller is: 1. Acquire all pictures at the largest format possible, in the best standard available, say in TIFF. 2. Never reduce greater than 50% without applying the 'Unsharp Mask'. 3. Reduce more, apply the mask and so on until the graphic is the right size. 4. Translate the object to either GIF or JPEG. I use Fireworks but I understand that ImageReady is equally as good. FW has a great export wizard, for optimizing the graphics for web use and I can see both the JPEG, GIF PNG results, side by side. The end result byte size can be preselected, the displayed images can be zoomed in and carefully checked and different what-if scenarios can be viewed, picking the number of colours, anti-aliasing, optimization, sharping, unused color removal, compression, adaptive colouring etc... I am still learning but the results are getting better all the time. Jim -----Original Message----- From: accessd-bounces at databaseadvisors.com [mailto:accessd-bounces at databaseadvisors.com]On Behalf Of Brett Barabash Sent: Monday, April 26, 2004 11:13 AM To: accessd at databaseadvisors.com Subject: [AccessD] RE: jpg Screen shot Huh?! I was talking about screenshots, not website buttons. As I mentioned earlier, IMHO, 20-40 KB is tiny for a screenshot, considering it displays 100% of the original quality. I have yet to find another file format that can top this. Nevertheless, let's do a little test here. Using Microsoft PhotoDraw 2000 (tried it with MS Photo Editor as well with reasonably similar results): ----- Source: 66x109 pixel 24-bit photo bmp file (a poor choice for PNG compression) Original BMP: 21,854 bytes PNG (24-bit color): 10,128 bytes PNG (8-bit 256 color): 3,052 bytes GIF (8-bit 256 color): 3,118 bytes (both the 8 bit PNG and the 8 bit GIF looked awful i.e. loss of photo detail/color) ----- ----- Source: 61x41 pixel 16 color toolbar button (a perfect choice for PNG compression) Original BMP: 9,438 bytes PNG (24-bit color): 391 bytes PNG (8-bit 256 color): 1,084 bytes GIF (8-bit 256 color): 1,129 bytes (results were identical. In this case, the 24-bit pallette netted a smaller file size, since there were only 4 distinct colors in the photo. The 256 color pallette wasted the additional overhead). ----- Keep the following in mind: - Photos are poor candidates for PNG/zlib compression. PNG works best for files with large blocks of the same color (e.g. screenshots). - All programs are not created equally. Despite LIBPNG being offered to software vendors and the general public with a free no strings attached commercial license, there are several apps that do a half-assed job of handling PNG files *cough IE*. What program are you using to convert to PNG? -----Original Message----- From: Robert L. Stewart [mailto:rl_stewart at highstream.net] Sent: Monday, April 26, 2004 12:28 PM To: accessd at databaseadvisors.com Cc: BBarabash at tappeconstruction.com Subject: Re: jpg Screen shot Tiny file size my foot!!!! I had to convert all my PNG (Fireworks) files to GIF to get speed loading them as graphic buttons for a web site. 94k compared to 6k. PNG was not a viable choice. At 12:00 PM 4/26/2004 -0500, you wrote: >From: "Brett Barabash" <BBarabash at tappeconstruction.com> >To: "'Access Developers discussion and problem solving'" ><accessd at databaseadvisors.com> >Sent: Friday, April 16, 2004 9:42 AM >Subject: RE: [AccessD] jpg Screen shot > > > > By far, the absolute best format for screenshots is PNG. Near-infinite > > color range (handles 32-bit palettes with ease), lossless compression, and > > tiny file size. > > ---------------------------------------------------------------------------- ---------------------------------------- The information in this email may contain confidential information that is legally privileged. The information is only for the use of the intended recipient(s) named above. If you are not the intended recipient(s), you are hereby notified that any disclosure, copying, distribution, or the taking of any action in regard to the content of this email is strictly prohibited. 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