Vegas doesnt natively suppourt still image sequence export but there is a script (called render image sequence) that provides this function. It will export image files sequentially numbered as per the frame rate of the project - ie 25 or 30 per second. But it will only export as PNG or JPEG files. Is there a particular reason you need TIFF? PNG will work just as well seeing as PNG suppourts alpha channel, field interlacing, is lossless compression with the added bonsu that PNG files are much smaller than TIFF in data size.

Importing is simple. In the preferences set the default still image length to 0.05 which will equal about 1frame at 29.97fps. Then you simply grab all the stills in one go from the explorer or project media and drop them to the timeline together. They will all go in sequentially.

Mikej