Spring painting is a traditional art form, which is common in China's ancient paintings and calligraphy works. It usually depicts the scene of spring, such as flowers and trees, birds flying, pastoral and so on. So no one in particular needs to write couplets to pave the way for the Spring Festival.
However, if we want to look for people related to spring painting from history, we can mention some famous ancient literati painters, who have performed well in painting and calligraphy, and may have made important contributions to the creation of spring painting.
For example, Wang Wei in the Tang Dynasty and Mi Fei in the Song Dynasty are famous for describing natural scenery. Their talents in painting and poetry make them likely to be considered as people who write spring pictures. But please note that this is just an example, not a specific answer.
The author of spring pictures has no fixed person. In the cultural tradition of China, many calligraphers, painters and literati will write couplets for the Spring Festival. In history, many people with artistic talent expressed their descriptions and feelings about spring through calligraphy, painting or poetry creation.
They may put pen to paper on the spring map to set off the scene and artistic conception of spring. These people include but are not limited to Wang Wei in the Tang Dynasty and Mi Fei in the Song Dynasty. However, in different times and regions, there may be other calligraphers, painters and literati who can also make couplets for Spring Festival couplets.
In short, the person who writes the couplet is not fixed, but is determined according to the individual's aesthetics and talent. Every artist has his own unique way to express his understanding and feelings about spring, so the author of spring pictures can be anyone with artistic talent and creativity.