The above is the standard size, you can change the size according to your own needs. There are no hard and fast rules. You can find your favorite size and set it. You know, the style and size of cards are also closely related.
A postcard is a card with an image written on it, which can be mailed directly without an envelope. Images can be photography, painting or design? Stamps with full face value must be affixed when posting. There is an image on the front, the postal code, address and name of the recipient are written on the back, and what you want to say to the recipient is written in other areas.
The advantage is that you don't need an envelope, but the disadvantage is that there is little space and no privacy. What is written on the postcard is public and can be seen by others. The content usually does not involve concerns about privacy, so it is called a clear letter. Postcard postage is cheaper than ordinary letters.
Extended data:
Postcard type
1, classified by issuing purpose and postal transportation mode, with wide coverage and strong science. Postcard collectors collect and sort out according to this method, and the compilation style of postcard catalogue is also determined accordingly. According to this classification, there are: commemorative stamps, special stamps, New Year stamps, tourist attractions stamps, Christmas stamps, donation stamps, military postcards, ordinary stamps, airmail stamps, pipeline stamps, special stamps and so on.
2. Classification by design form. The design form of postcards can attract people's attention and arouse the interest of collectors at all levels. Such as art postcards, book postcards and advertising postcards; Non-paper postal film, such as plastic pressed three-dimensional postcards, wooden postcards, etc.
3. According to the postage utility of postcards, there are local postage stamps, foreign postage stamps, international aviation, stamp value change, free, postage paid, pre-sale postage stamps and so on.
4. Thematic stamp collecting is classified according to the graphic content on postage postcards and named after the thematic name. If the pictures and texts have dance material, they are called dance postage films.
5. Some philatelists classify the stamps actually sent, that is, first day stamps, registered stamps, stamps with various stamps or postal labels, such as stamps with local surcharge labels, and so on.
References:
Baidu encyclopedia-postcards