batch conversion tiff to jpeg

Installed Gr and works great. Only problem I have is that I have a ton of tiff images to be converted to jpg for up load to gallery. So far i have not been successful on finding a program to my liking. ie. one that allows some degree of control over output size and file compression/quality. Can anyone lead me to what I am looking for. Otherwise its goning to be one a time via photoshop. :???: