What is a Jewish artist not allowed to create? Sculpture, painting, etc.
Sculptures cannot be made of people (this applies to the head and face alone, and also to the entire body even without the face), the celestial bodies (the sun, moon and stars) and the signs of the Zodiac (according to the Shach 141 this refers to all the Zodiac signs together).
There is a dispute as to creating flat images of the sun and so on, and the general consensus of later authorities is to be stringent for this matter.
Flat images of a person are permitted (according to most authorities). For sculptures, the Chasam Sofer (2:128) suggests leaving out some part (such as an ear or eye) and allowing this to be completed by a non-Jew.
The sources for this matter are complex, and there are many opinions among Rishonim to Avodah Zarah. The following are some basic sources:
See Avodah Zarah 43a-b; Rambam, Idolatry 3:11; Shulchan Aruch, Yoreh Deah 141:4; Taz 141:13 (permitting flat images); Shach 141:25 (prohibiting flat images); Chochmas Adom 85:5, Kitzur Shulchan Aruch 168:1, Iggros Moshe, vol. 5, no. 9; Rabbi Pesach Eliyahu Falk, Am Ha-Torah, mahadurah 3, vol. 5, pp. 49-70; concerning gerama, see Lehoros Noson (3:50), who permits the creation of an image by means of gerama. The question of what precisely constitutes gerama is complex: see Rabbi Yitzchak Halperin, Maaseh U-Gerama Behalachah.