Image Resolution Help

Anyone have suggestions for developing images in Photoshop and transfering them to Flash?
For instance:

File type: is it best to save as a .jpg, a .tiff, or some other format? and why?

Image size: how big is big enough to ensure that you won’t end up with dithering?

Resolution: what resolution do you guys normally do your design work in? Images for use on the internet are normally fine at 72 dpi, but is that what you save your work at? or do you save your work under a high resolution and then scale down the image when importing into a program like Flash?

Just looking for a few suggestions.

Here’s a link to an image I’m dealing with… the final version will have the book opening and closing (the 2nd link I include). I’m worried mostly about file size bc as it stands now I created a separate layer for each frame of the image and then imported each image into Flash MX.



My other issue is with transparency. I’d like to just take the shield in the background out and put it on it’s own layer in Flash, but the black from the book image covers up anything below it on the page.