With ImageJ 1.x, a special HandleExtraFileTypes plugin exists that can be modified to support new data formats—but it has some significant disadvantages: It only provides limited extensibility: there can only be one HandleExtraFileTypes installed into ImageJ at a time, so all desired modifications to the plugin must be somehow combined. This makes it impossible to, for example, ship a different HandleExtraFileTypes on two different ImageJ Update Sites and have both additions be available in the same installation. Data formats added in this manner cannot override or extend ImageJ1”s built in support for certain file formats. In particular, ImageJ1 supports only a subset of the TIFF specification, and this issue cannot be circumvented via HandleExtraFileTypes modifications.