All RPG Makers: How to make a picture's background colour transparent?

Umm......Can anyone teach me how to make a picture's background colour transparent but not in  a RPG Maker program...Easier description: HOW DO YOU MAKE A PICTURE'S BACKGROUND WITHOUT DOIN IT IN RPG MAKER?

Use Photoshop or any other advanced image editing program.

Depends what you mean...

You can't make BMP, JPG and a few other types of files with a Transparent Background... PNG's and GIFF are the most common to have transparent Backgrounds...

I think it is a pain to manually 'transparent' a character sprite I want. I do it by magnifying the said-sprite to 500% and slowly erasing the unwanted regions with the eraser tool in photoshop.

Anyone got a more efficient way to go around it than compared to mine?

I don't any more efficient method. =/ I do it the same way when I do the fine work. It's quite a laod of work, but I think it pays of.
You can try to select the outer part with the magic selection (forgot the exact name...) tool and delete it once or a few times. This can boost up the process and you only need to fine-do a little bit.

@LoS: .tga has transparent background, too, I think. I'm pretty sure it does.

Sry...but I don't get it...

Well for starters, you need some kind of image editing program; like what Blizzard had stated earlier. I use photoshop for such kind of task.

Then just load the picture up into the chosen editing program and manually erase/delete the area you want to be transparent. Upon completion, save the picture as .png, .gif etc. Those types can display transparency.

I guess that's about it.

You mean I have to use Photoshop and such and just use the eraser?

Do you have photoshop? If so, there is actually quite a few ways for you to choose other than the standard eraser tool.

You can use Marquee or Lasso tool if you intend to cover huge areas. Or simply the Magic Wand tool (convenient but somewhat unreliable). Edit->Clear those selected areas and you will get your transparent background.

The eraser (min.1px) is for stuff that require more delicate procedure; e.g. character sprites.

Remember to save your work in transparency-compatible filetype, or it won't turn out transparent.

Yes, magic wand tool, that was the name I couldn't remember.

Or create New project in photoshop and chose Transparent background (standart is White Backroun)
Use new Layer and paste picture and changet opacity.

WOW! Thanks all for your help!