texture and transparency

There’s this thing I’d like to do and I’ve tried it without much success. I don’t know if I’m doing it wrong or if it’s doable at all. I want to place a simple flat, rectangular plane in a scene and render it completely transparent, so it’s invisible in the scene. Then, I want to project (texture) a .gif image onto the plane. The image itself has transparent elements in it. The idea is that the visible parts of the image will be visible in the scene, while the transparent parts- and the plane (object) it’s textured on- will show clear, and show the scene beyond. So far, because the plane is transparent, the image renders completely transparent too. (The image can be made partially visible by adjusting the reflectivity of the object, but this is the totally wrong effect. It shows no color at all, just reflected light.) I want to see the visible parts of the picture in the foreground and the original scene, in the background, through the transparent parts. Anyone know if this can be done?

yes, but gif format does not support transparency. PNG and TGA do, though. JPG does not. see http://wiki.blender.org/index.php/Manual/Output_Formats#Options for a list.

That “projection” of an image onto the plane is called texturing, and you want to UseAlpha of the image to make the corresponding portion of the plane transparent. see http://wiki.blender.org/index.php/Manual/Textures

Thanks so much for the links. I studied the tutorial and it works well.
Just to set the record straight, the .gif extension does support transparency. Out of curiosity, I tried both .gif and .png in Blender, and they both work fine. I haven’t decided which is better. Probably .png.
Thanks again for your help, Papa.