Many basic digital photo packages like Apple's iPhoto for Mac OS X have some very powerful features which used to only be available for high end graphics platforms like Adobe Photoshop.

Nevertheless, if Photoshop is available, it makes editing stuff out of digital photos a snap. The method explained in this video is one way to basically remove an item from a uniform background like grass or a wood floor. The other method uses the same principle but can be quickly applied to a much larger area.

Simply put, if there is an area with the uniform texture that is the same size or bigger than say, a rock that should be removed, simply use the lasso select tool to select an area of that uniform background, copy it, then paste and move it to cover the rock. Once placed, flatten the image and use the blur and smudge tools to clean up the edges so they don't look clipped.

This probably wouldn't work so well with grass as the background but it is awesome for cement or a solid color wall.