one other question... in photoshop 5.5, how do you make an object (for example, a table) and preserve the transparency so that you can drop it on top of another tile in Maptools? I should know how to do this, but for the life of me I cannot seem to do it!
You save them as PNG files though there is probably a setting in Photoshop that says to preserve transparency. I use Gimp so can't help you with the specific setting.
When saving images that have a transparent area around them use whatever the feature in Photoshop is called that allows you to automatically crop away the unneeded portions while preserving the drop shadow.
Photoshop 5.5 is pretty old. I don't remember what its PNG support was like. Modern versions do let you preserve transparency, but only as a PNG-24. PNG-8 does support transparency, but not through native Photoshop controls.
The command you are looking for is Trim. You have the option to trim away surrounding fully transparent pixels, while preserving drop shadow, glows and the like.