A method for classifying pictures, comprising steps of: obtaining (101; 201) pictures to be classified; determining (102; 201) a class of each picture according to feature information of the picture, wherein the class comprises a text picture class and a non-text picture class; classifying (103;203) the pictures according to the class of each picture; characterized in that the method further comprises steps of: if the picture belongs to the text picture class, obtaining valid time information and current time information of text information in the picture; detecting whether an expiration time of the picture exceeds a first predetermined period according to the valid time information and the current time information; and if yes, deleting the picture; wherein the step of obtaining valid time information and current time information of text information in the picture comprises steps of: reading the valid time information from a text recorded in the picture; obtaining the current time information; wherein, obtaining the current time information comprises: extracting the text from the picture by OCR; extracting time information from the text information according to keywords; determining the time information as the valid time information. obtaining (101; 201) pictures to be classified; determining (102; 201) a class of each picture according to feature information of the picture, wherein the class comprises a text picture class and a non-text picture class; classifying (103;203) the pictures according to the class of each picture; characterized in that the method further comprises steps of: if the picture belongs to the text picture class, obtaining valid time information and current time information of text information in the picture; detecting whether an expiration time of the picture exceeds a first predetermined period according to the valid time information and the current time information; and if yes, deleting the picture; wherein the step of obtaining valid time information and current time information of text information in the picture comprises steps of: reading the valid time information from a text recorded in the picture; obtaining the current time information; wherein, obtaining the current time information comprises: extracting the text from the picture by OCR; extracting time information from the text information according to keywords; determining the time information as the valid time information. if the picture belongs to the text picture class, obtaining valid time information and current time information of text information in the picture; detecting whether an expiration time of the picture exceeds a first predetermined period according to the valid time information and the current time information; and if yes, deleting the picture; wherein the step of obtaining valid time information and current time information of text information in the picture comprises steps of: reading the valid time information from a text recorded in the picture; obtaining the current time information; wherein, obtaining the current time information comprises: extracting the text from the picture by OCR; extracting time information from the text information according to keywords; determining the time information as the valid time information. reading the valid time information from a text recorded in the picture; obtaining the current time information; wherein, obtaining the current time information comprises: extracting the text from the picture by OCR; extracting time information from the text information according to keywords; determining the time information as the valid time information. extracting the text from the picture by OCR; extracting time information from the text information according to keywords; determining the time information as the valid time information.