Usually, the gif you are talking about is a picture format, which is what you often call a dynamic picture. I will often see it on the internet now. Different from some previous expression packs, it is a gif dynamic picture, which looks more vivid. It can better express the sender's current mood and content. So it is very popular with netizens. However, if you add the word serial number, the whole meaning will change greatly!
Many people think that the word serial number first appeared in Japan. In fact, the word "hyphen" has long appeared in China. It's just different from the understanding of serial number in Japan. Serial number refers to the meaning of the number, such as telephone number, room number, etc. Now it is often called Japanese vulgar movies and comics. For example, a video or album will have its own serial number.
If the words "the origin of gif" are connected together, the meanings will be quite different. This word usually refers to the website number of some indecent videos. Sometimes I see a netizen asking the source of a gif number on the Internet, which means to find the number of some videos or websites.
What looks vulgar has also been replaced by these nouns. I don't know. I thought it was something tall. But the old drivers are well aware of this. If you see this statement in the future. There is no doubt that it refers to these contents. So even if some people don't understand, remember to check online. Don't ask such ignorant questions when there are many people. You'll make a fool of yourself in public!