How I can make the foreground layer go "front of" the sprite layer, and background go "behind" the sprite layer???

Right-click the main screen and select layers with numbers above 4 to get background layers and smaller than 4 to the foreground layers. Layer 4 is the sprite layer.

They are in right places, but when the background/foreground is in the background/foreground layer, they are same size like in sprite layer. How to fix this?

Change the relative movment propertys.

You can do that to make the 3 layer and 5 layer the SAME size as layer 4.
And the X-Speed and Y-Speed much be 1.

Yes, but my problem is that how I can make the background sprites smaller because they are blocks and hooks etc. so how I can make them smaller and bigger in foreground?

Originally Posted by ZelectaMan

Yes, but my problem is that how I can make the background tiles smaller because they are blocks and hooks etc. so how I can make them smaller and bigger in foreground?

Uh, you can't.

New question: How I can upload a background from my computer to JCS?

lawl you have to compile a new tileset to do that.

Okay... Ill do that... Thanks anyway...

JJ2 does not include any built-in functionality for zooming or resizing tiles in other layers. You have to either use a tileset like Carrotus or Psych which already has resized tiles to use, or make your own tileset with resized graphics in addition to the originals.
For that, I suggest Disguise's Tileset Resource, which talks all about making your own tilesets.