I'm one of those people who have ideas but cannot get my head around the more complex scripting to achieve them. This is going to be hard to explain but I'll give it a go and hope you can help me out a little.

I'll try and make the explanation as basic as possible.

Say I have 4 Rows, divided into 20 equal sized slices each as below
 _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
Each of these slices represents a measurement, lets say 1 Slice = 10 pixels wide, they are all equal in height.

--- Here's the hard part ---

What I would like to achieve is way of dragging an image onto either row and then the image snaps to position anywhere in the row (snapping to the nearest slice). But, each each image has a different width, which is a multiple of 10 in width. So some images fill only 1 slice but others 4. I would also like to move these image around the rows by drag and drop and remove the image by dragging to a trashcan or right clicking.

Also if a row is nearly full of images and you try to drag on an image which wont fit it will turn red or something to indicate this and not let you drop it.

I have no idea where to start in scripting this and if possible would appreciate any snippets people can offer for me to try out and expand upon.