how do you make a border around a picture using photoshop 7?

Answer 1

Select the picture using the rectangular marquee tool.
In the Layers palette if the picture layer is set as Background double click on it and set as Layer 0. Now click on the Add Layer Style button and, on the menu, click on Stroke.
In the Layer Style window choose the size and the color of the stroke, in the Position box select Inside. Confirm with a click on OK.