What is diagonal length of an Image and How can I calculate diagonal length of an image?

I want to calculate diagonal length of an Image....

Answer 1

[Star Strider]

Im = imread('Polar_Bear_With_MATLAB_Hat.png')
ImSz = size(Img);                                               % Get Dimensions
DiagLen = hypot(ImSz(1), ImSz(2))                               % Invoke Euclid To Get The Diagonal Length

[K M Ibrahim Khalilullah]

Is it for square image or any size?

[Image Analyst]

Any size. The answer is in pixels, not real world units. For that, see my attached spatial calibration demo.

[Star Strider]

Square or rectangular only, but any size that can fit in your computer. Other shapes require the typical specific geometric metrics for them, but they are all still likely to be squares or rectangles originally, simply because that is how the majority of imaging devices format them.