bug in map and image

What is happening here?
```m2
i1 : f = vars(QQ[x,y]);

i2 : map(image f, , f)
stdio:2:1:(3): error: expected matrix and new target module to agree
```
Note: I understand that `inducedMap` works here, but that method can be computationally expensive (e.g. computes Grobner bases in some cases) which seems unnecessary for what the code above should do.

Start by reproducing the reported map(image f, , f) example in a Macaulay2 session and compare its behavior with inducedMap, which the report identifies as working. Trace the map implementation far enough to determine why the matrix and target module are rejected; done means the reported example works without requiring the computationally expensive inducedMap path.

Written by the indexing model from the issue text.