1. This paper gives a survey on image morphing methods in terms of feature specification, warp generation methods, and transition control. 2. Image morphing is realized by coupling image warping with color interpolation. Image warping applies 2D geometric transformations to the images to retain geometric alignment between their features, while color interpolation blends their colors. 3. Key steps of image morphing: 3.1 Establish correspondence between two images with pairs of feature primitives. 3.2 Compute mapping functions, which define the spatial relationship between all points in both images, using feature correspondence. 3.3 Generate inbetween images through color interpolation after both images have been warped into alignment for intermediate feature positions. 4. Key morphing methods: 4.1 Mesh warping 4.2 Field morphing 4.3 Radial basis functions/thin plate splines 4.4 Energy minimization 4.5 Multilevel free-form deformation 5. Transition control determines the rate of warping and color blending across the morph sequence. 6. Future work 6.1 Morph among multiple images. 6.2 Improv automatic morphing among a limited class of images and video sequences.