Changing a border colour in Photoshop is extremely simple, once you know where to look. The majority of quick Photoshop effects are located within a section called "Layer Styles." This menu contains effects like drop shadow, outer glow, etc. Although we use the term "border," Photoshop does not use this term. Instead, the "Stroke" effect creates or alters borders on an element. Changing the stroke can cause an element to pop from the background and pull greater focus, depending on the background.
Open the file you would like to work on in Photoshop.
Select the layer that contains the object whose border you'd like to change. If need be, select the specific object (only for object-based images).
Click "Layer" from the menu at the top of the program window.
Highlight "Layer Style" and click "Stroke."
Change any stroke attribute you see to achieve your desired look. Click "OK."
Checking the "Preview" box in the "Stroke" window lets you view the changes as you make them. Strokes can be in three different types: colour, gradient or pattern. Click the drop-down menu "Fill Type" in the "Stroke" window to choose one of the three. Strokes can be put on anything in Photoshop - not only boxes.
If the border you'd like to change is part of a JPEG image (and not a Photoshop file), you must isolate and select the border area to change its colour manually.