Change the color of an image border

Hello. How to merge images vertically and horizontally by changing the color of the matrix cell indicate with green and red.

Answer 1

[Image Analyst]

No idea at all what this (what you asked : "Hello. How to merge images vertically and horizontally by changing the color of the matrix cell indicate with green and red.") means. See link below before you fix your post.

TUTORIAL: How to ask a question (on Answers) and get a fast answer

so all I can offer other than the link above is to look at imtile() or montage() to stitch images together, or to do it manually:

tiledImage = [image1, image2; image3; image4];