Anisotropic triangulations are utilized in recent methods for sparse representation and adaptive approximation of image data. This article first addresses selected computational aspects concerning image approximation on triangular meshes, before four recent image approximation algorithms, each relying on anisotropic triangulations, are discussed. The discussion includes generic triangulations obtained by simulated annealing, adaptive thinning on Delaunay triangulations, anisotropic geodesic triangulations, and greedy triangle bisections. Numerical examples are presented for illustration.