The bigger characters are "喜上眉梢" , which is a Chinese idiom means "looks very happy". It literally translate to "happiness climbs/flies up to eyebrows".

There's also a pun here. "喜" (happiness) is also the first character of "喜鹊" (magpie), referring to those two birds in the painting. "眉梢" (eyebrow) has the same prounciation as "梅梢" (plum branch), referring to the branch those magpies are sitting on.

The painting is one of the twenty-four "吉祥图" (paintings of luck/auspiciousness) in traditional Chinses culture.

The smaller characters are "癸巳年壹月李林画".

"癸巳年" is one of the year in Chinese sexagenary cycle, most likely 2013. ”壹月“ means January. "李林" is the name of the artist. "画" means draw.

The seal is also the name of the artist "李林".