newbie in photoshop

The JPEG protocol doesn't allow for transparency. Only GIF and now PNG alow for transparency. Use GIF until PNG is more widely accepted.

One more thing when you're saving a .gif to use on a background. If you don't want those cheesy jagged edges, pick the color of the background to add to the .gif.

You would go to FILE>SAVE FOR WEB and then you would check "transparency" and on to "matte" and go down to "other" then punch in the color code as the background your image will go on and it'll fit seamlessly and lots cleaner.

Cheers!

I would think u usualy don't need to use transparancy then: u often can just give the whole background of the image the color of the background of the site. Ow, yes I guess tansparancy makes the fileize smaller. Anyway I usualy pick a color for my matte the color of my image itselfs. This way my image looks better on all backgrounds I guess. I don't know if this is a good tactic... and it probably won't work well when there are to much different colors in (the border of) ur image.