How to get a portfolio for Programming & Tech gigs?

[ninjanic]

Hi!
I wonder, how does one add to their portfolio on a programming & tech gig? Under “send work” I sent a buyer the screenshot, but he said he could not find the option to add it to the portfolio. The next order, I then switched it, and sent the picture under “send source code.” Still nothing.
I know this is possible, because I saw another programming gig with portfolio images in it:
https://www.fiverr.com/ymittal283/do-java-assignments-java-projects-remove-errors

Can somebody please help me with this?
Thanks!
~Nic