This is an old question, but since it's very popular, I'm going to add my share of information to it.
As all other answers says, you have to convert the tiff to some supported format by LaTeX. All other answers suggest to convert to png, but I think that it is best to convert directly to pdf.
There are many reasons for this, because tiff is a container format that has many common features with pdf:
- it supports different color spaces, and so if the original image is in
ymck for example, you don't have to convert it to rgb (which is the case with png);
- it has different king of compressions, most of which are supported by PDF, and so if the original image is black and white scan compressed with
ccitt, you don't have to convert it to ten times bigger png;
- it support vector clipping paths that can be preserved in the
pdf.
For all these reasons, I think that is better to use something like tiff2pdf in place of convert to png.
libtiffhad a horrible security history. And dropping it made the binary much smaller. – Martin Schröder Jan 16 '13 at 19:37