... After the release of the successful WFPC2 associations, the CADC, ST-ECF and STScI are now working on joint pipeline software to produce associations of images from the HST's Advanced Camera for Surveys instrument. Although the basic approach is very similar to the WFPC2 associations (Durand et al., 2004) there are some fundamental differences because of the high level of geometric distortion of the ACS optics. ... Figure 1: An Example of a Complex Association of ACS Images. ... Images . ...