I am using Vegas 7 to make some photo montages for professional photographers. Which format is the best to use for digital images.......jpeg, psd or png?
The only format I'd recommend you stay away from, is the .tif format, as it requires an external reader. This hogs resources and slows down the process, and depending on a few factors, can bring the best system to it's knees.
All three will work so it might boil down to what the photographers want to give you. If you don't have your own copy of Photoshop ten maybe you should ask for PNG files, or high quality JPG files.
PNG is a lossless format that can also include an 8-bit alpha channel. The alpha probably won't be useful for showing off a photographer's work. PNG files don't usually compress down very small (not for photos, anyway) but they faithfully preserve the quality of a photo and are just as good as PSD files as far as Vegas is concerned.
JPEG is lossy and can degrade an image. However, when you create jpeg images you can specify the amount of compression used. If you are trying to preserve image quality you certainly can do so simply by using very little compression.
Photoshop has a "Save for Web" tool that allows you to play with compression types and compare the results. Very useful, very informative.
Other things to consider. When you compress a file and then drop it on the timeline, Vegas (or any other program) has to decompress it into RAM. The amount of space a compressed file takes up on disc is always less than what the decompressed file uses in RAM. The point here is that even though JPEG compression creates smaller files than PNG, they still take up comparable amounts of space in RAM when in use. (I'm not sure if this is the same with PSD files, maybe they can be larger on disc than in RAM?) So if hard drive space (or CD/DVD media space) isn't an issue then you should ask for PNG because the quality is better.
Vegas performs very well with PNG files so that's the format I'd ask for. Your photographers may be very used to TIFF but ask them for PNG instead, or use the PSD files if you have a current version of Photoshop. As Spot says, Tiff can be very problematic.
Hmmm. What else? Image sizes. I don't know what your final output will be but of course a progessive HD format will look best. If going to standard def NTSC and you want to just fill the frame I'd use 720x528. That's a multiple of 654.5x480 and has the advantage of being actually possible (all whole numbers). Of course if you want to move or scale the image you'll want to use larger images.