I generally don't do photo montages. However, I agreed to do a 200 pic photo montage for a friend. Scanned all pics and saved as jpegs - Exported to media encoder and it's taking forever to encode (going on 20 minutes now). what is the best file format to do this in: jpeg, bitmap, targa, etc. I generally don't like to do pics and when I do it's only about 20, so this is 10x the amt. Thanks for your help.
The best format, IMO, is PSD, the native format of Photoshop.
Also, in PS, do yourself a favor (on two fronts), and Scale the images to match exactly, or very nearly so, the Project/Sequence Preset. The quality will be better, and the system overhead will be smaller.
This ARTICLE will give you tips, and a bit of background on Scaling still images in PS. Note: the dimensions listed are for an SD DVD Project. If you are doing an HD Project, just plug in your pixel x pixel dimensions.
Also note that JPEG is a compressed format, and data will be discarded. That is why I use and recommend PSD, and this is especially true if the camera shot JPEG to begin with - double JPEG will look worse.