This application discloses an imaging composition employing a tellurium compound sensitive to activating radiation. Such imaging compositions have been disclosed in a number of earlier patents, such as U.S. Pat. Nos. 4,142,896, 4,066,460 and 4,106,939. This application discloses improvements in the foregoing imaging compounds employing glycerol ethers or glycerol thioethers of the formulaR.sup.7 --X--CH.sub.2 CHOH--CH.sub.2 OH