Just generated a tif-file from a jpg-file with Slowview. But when placing it in a document (Insert-> Picture) its a black field with some green snow on it. Repeated the procedure with another picture - same result.
Atlantis supports TIFFs (revision 6.0) of the following subformats:
Packbits, CCITT G.3/G.4, LZW.
If your TIFF is of another subformat, Atlantis will not be able to insert it.