How to reduce PNG size

[Abbie]

Some times i create graphics for web, and while doing that i prefer the PNG format images. but due to its huge size, the loading time increases. So i need any way to reduce PNG size either manually or using any third party application. Do you guys have any best suggestion of doing that ? please help.

[Sam.D]

PNG format images are good enough for creating graphics on the web including cliparts, buttons, headers, footers, borders and so on. In order to reduce or compress the PNG file size, You can use a handy utility called as PNGOut. It optimizes the size of .PNG files. It is really very useful at the end of a project to just drag all the PNGs from a folder into the app, get them shrunk, and then upload to the live server. It can optimize almost all .PNG files on the .website. It can be run from the Windows Run dialog box or at the command prompt. i have some useful tips for using PNGOut:

• /d# : select the color bit depth: {0(minimize),1,2,4,8}
• /s# : select strategy: {0(default),1,2,3,4}
• /k# : keep or remove ancillary (optional) chunks.
• /c# : select the color type: {0,2,3,4,6}
• /f# : select the filter type: {0,1,2,3,4,5}

Download PNGout

[Raine]

You can also compress PNG files easily using OptiPNG. OptiPNG is a PNG optimizer that recompresses image files to a smaller size, without losing any information. This program also converts external formats (BMP, GIF, PNM and TIFF) to optimized PNG, and performs PNG integrity checks and corrections. OptiPNG sometimes produce 50% smaller output and it runs faster.The PNG compression works in a pipeline manner.

In the first stage, the image pixels are passed through a lossless arithmetic transformation named delta filtering, or simply filtering, and sent further as a (filtered) byte sequence. Filtering does not compress or otherwise reduce the size of the data, but it makes the data more compressible.

In the second stage, the filtered byte sequence is passed through the Ziv-Lempel algorithm (LZ77), producing LZ77 codes that are further compressed by the Huffman algorithm in the third and final stage. The combination of the last two stages is referred to as the Deflate compression, a widely-used, patent-free algorithm for universal, lossless data compression. The maximum size of the LZ77 sliding window in Deflate is 32768 bytes, and the LZ77 matches can be between 3 and 258 bytes long.


Download OptiPng from the attachment with this post

[ThoMas321]

When i was in search of a tool for doing the same job, i tried PDF Compress 1.00 and find it very useful for me. Reduce the actual size of PDF files by compressing text and graphics.Compressed PDF files may be opened and viewed normally by all Adobe Acrobat Reader's versions. You can download PDF Compress 1.00 from here.