Frames First, Images Second
When you have to place a number of images into your layout, save yourself some effort and first set up the graphic frame with particular specifications (Fit Proportionally, fit content to frame, fit frame to content, etc.). That way you won’t have to fidget as much to make the fit.
Drag out the frame to the desired size and proportion. Select Object > Fitting > Frame Fitting Options. Define the Crop Amount or the Reference Point (the point from which your sizes will emanate), and select Fitting > Fit Content Proportionally. Once you define one frame, Option/Alt-drag it to make a duplicate with the same parameters. Now when you Place (Command/Ctrl-D) an image, it will come into the frame with the predefined sizing.
This tip applies to InDesign CS3 and CS4.