We are a free gif material site Freegia-freeGifArt-.
 This site mainly allows you to download animation-based transparent Gif.
All can be downloaded for free and can be used for commercial use. (For details, please refer to “About the use“.)
 We hope you find it useful for creating websites, videos and PowerPoint materials.
Also, if you have requests for additional materials or requests for improvement, please contact us from “Inquiries / Requests“.

Transparent GIF

A transparent GIF is an image file that has one color assigned to be “transparent” so that the assigned color will be replaced by the browser’s background color, whatever it may be. Pretend, for example, that you have created a rectangular GIF image of a large red star on a white background. If you are only interested in having the red star appear on your Web page, and don’t want to see the white background, you can transparentize the white background color so that it changes to whatever the Web page’s background color is (yellow, for example). Then, when you view the Web page, you will only see a red star on a yellow background.

-Source  whatis.techtarget.com-