According to the MLA Handbook for Writers of Research Papers (7th Edition), you should use the author's last name and a page number for citations and begin the Works Cited entry with the author. With other works such as pieces of art, especially when no artist is credited in the original source, different rules clearly apply.
MLA citations tell your reader where you got your information. If the work of art you cite has no discernible artist, use the title of the piece in the context of the sentence or in the parenthetical citation to clarify your reference. You can write a shortened version of the title as long as the citation begins with the first word of the piece's title. For instance, shorten "Flowers on a Summer Evening in Paris" to "Flowers." Place titles of art pieces such as paintings and sculpture in italics throughout the paper, including in any in-text citations.
The rest of the bibliographical information about the work of art appears on the Works Cited. Begin your entry with the title of the piece, italicized, capitalizing the first word and any subsequent important words, followed by a period. Then give the date and a period if known. If not, type "N.d." State the medium, such as "Marble" or "Etching" (without the quotation marks) with a period. Finally, explain the piece's location, such as "Museum of Modern Art, New York" (without the quotation marks) and a period. Such an entry might appear like this: Flowers on a Summer Evening (italicized). 1970. Watercolor. Private collection.
If you found the work in a book or on a CD or Web page, add detail about that source at the end of the entry on the Works Cited page. Add regular book information for a text: title of the book (italicized), "Ed." (without the quotation marks) and the editor's name with a period after each, and then the publisher information. Give the city, a colon, the company, a comma and the year the book was published, followed by a period. Give a plate, page or figure number to clarify where it appears and a period. Then give the type of publication, such as print, ending with a period. For a digital file, instead of this book information, add the type of file, such as JPEG file, after the location information, ending with a period. For a piece from the Internet, leave out the medium of the artwork, such as watercolor, and add the site information at the end of your entry. Give the name of the site, italicized, with a period. Then write "Web" (without the quotation marks) with a period and the date you accessed the site, day-month-year: 10 March 2013.