Most VT(T)'s use a normal JPG / PNG or something like that as a backdrop for all the static stuff. Anything that moves or might need to be altered, or is hidden from players - as part of the gaming - like characters, monsters, doors, pits, etc are all done with tokens on top. Tokens are also just smaller PNG images which the VTT app puts on top of the backdrop to make up the scene. Its like those books of stickers you used to get as a kid where you place them on the printed card sheet backdrop.
For scale it depends on whether you plan on viewing it on screen or whether printing it out. For VTTs thats normally on screen. So taking about a real inch of screen space for a characters 5 foot base which is say 100 pixels that would be something like 20 pixels per in game foot. So a 15" wide monitor could show about 15 * 5 ft of in game dungeon or 75ft which would be 1500 pixels. Yeah ? Now some apps can deal with more or less res than others so it depends on what your using too.
If the map is for a VTT but you dont have one then you can make the backdrop and the movable items as separate PNG files. Theres several free VTTs out there inc MapTool, DungeonForge, GameTable and RPGTonight. You can also use the layers in Gimp or use an HTML web page with style sheets to place down the tokens at specific places if your feeling really nuts.
Thumbnail entrants below as usual...
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### New Challenge Entry:Drahyden,5428
### New Challenge Entry:Gamerprinter,5434
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### New Challenge Entry:MysticMagellan,5562
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