display uploaded image in block, how?

I uploaded several images into the files directory and now i want to use one of those in a block. I just added which worked fine on the mainpage, but when i click to a node, the relative path is not correct anymore (obviously) and no image is displayed.

Full path is not working as i'm using localhost and when someone else accesses the site, it's not localhost and doesn't work. I tried the module 'inline', but couldn't get it to do anything (i think you need to upload the image to a page and use it in there, instead of in a block?). I tried image and image_attach, but i couldn't find a way to put it into a block.

How can i solve this?