I need a favor, I want to make a file field for images, this is done, but y want that in this field when I choose a image, the field shows a miniature image of the image that I have choosen.
Well. There is no way showing a picture without uploading it first. At least not with PHP. You can use JAVA or anything else for that kinda thing.
Otherwise you must upload upon selecting the picture with a hidden iframe or that kinda thing that returns an url of a thumbnail pic. There are a lot of examples if you google for that.