Some image file formats, like PNG or GIF, use only lossless compression, while others like TIFF and MNG may use either lossless or lossy methods.
JPG (= JPEG) and GIF, destroy some of the image data during the file-saving process. For that reason, you should save in JPEG or GIF only after you're completely done editing, and only if you want to use the picture for some purpose that requires one of these formats.
Transparency isn't the only advanced feature that PNG boasts over GIF. PNG images can also contain a gamma correction value, which is meant to represent the relative brightness of the display on which the image was created. In theory, the browser can use this value to display the image at the exact same brightness on another display.
That's all well and good, except that other image formats and solid colours specified with CSS do not contain this gamma correction value, so when you adjust the display of a PNG based on its gamma information, it no longer matches the other colors on the site.
For this reason, most browsers (including current versions of Firefox, Safari, and Opera) ignore the gamma correction value in PNG images when displaying them on the Web. But Internet Explorer does not, and that's why my PNG images stood out in that browser.
The solution to this problem is to produce PNG images with no gamma correction information in them, so that Internet Explorer will not attempt to correct their display. Unfortunately, Photoshop's "Save for Web" feature doesn't give you that option, so you need to use a separate tool to strip out the gamma correction information that it writes.
A great tool for doing this in Windows is TweakPNG. It's open source and a free download. Simply drag a PNG to the program window and delete the "gAMA" chunk from the list before saving the file. While you're at it, you might as well delete the "tEXt" chunk as well, to save a few extra bytes of file size by removing Adobe's stamp on the file.
PNG was designed for transferring images on the Internet, not professional graphics, and so does not support other color spaces (such as CMYK).
PNG itself does not support animation.
PNG offers a variety of transparency options.
PNG-8 - 8-bit - similar to GIF - more advanced compression than GIF, lossless compression
PNG-24 - 24-bit - similar to JPEG, lossless compression, may be larger than JPEG
offer DivX files in a highly compressed version of the MPEG-4 format used by corporate outfits like Microsoft and Real Networks. Because of the powerful DivX compression technique, which is called a codec, these files can be relatively small and yet contain high-resolution movies that play in full digital grandeur on a PC or Mac monitor.
MyDVD uses a simple drag-and-drop interface that allows users to combine video, audio, text and pictures into "video postcards" with up to one hour of high-quality video on a low-cost CD recordable disc. US$50
Video DownloadHelper :: Add-ons for Firefox - Download the YouTube video as MP4 file.
- Complicated to get set up and there are annoying warnings that you must register the US$28.50 converter. Annoying logo (QR code) is always in the video.
US$28.50 "registration" is required if you don't want the
in the video, if you want to
convert videos directly to mp3 audio files, if you want
access to support for the conversion feature.
In PowerPoint 2013, you can insert and playback many different video and audio file formats.
For the best video playback experience, we recommend that you use .mp4 videosencoded with H.264 video (a.k.a. MPEG-4 AVC) and AAC audio.
For audio, we recommend using .m4a files encoded with AAC audio.
Important Certain older video file formats may not compress or export properly in Office on a Windows RT PC.
Instead, use modern media formats such as H.264 and Advanced Audio Coding (AAC), which PowerPoint 2013 RT supports.