Hello @kerevilas! You do need to link a portfolio, since that’s the best way for your skills to be evaluated as a builder. You just need to post the photos to some public space, usually Imgur or something similar, and then put the URL/link in that question response.
You should take a look at this accepted Build Team Application for some examples and ideas as to what they look for in an application: OreoMilkshakeYyz Builder Application - #6 by Zammyz