A design portfolio is a showcase of your skill.
It may be the one thing that separates you from a 'Maybe' than a 'No' list. It's the door to getting called for that job interview. Failure to attract the hiring managers' attention means you are letting go of job opportunities.
A design portfolio must speak for itself because you won't be there to explain it when you submit that job application. Now, what can you do that?
Present your work in a layout, and create a mockup. The presentation of your work matters. Think of the portfolio as a design task of its own.
Your options: Portfolio sites such as Carbonmade, or Issuu (upload PDF). Behance and Dribbble are good too. If you're in UI/UX, it's GREAT if you can showcase it on your own portfolio site.
Remember, hiring managers have a lot of portfolios to go through. So your portfolio has to stand out.
You don't have to show everything. Only show the ones worth talking about.
Organize your work according to categories. If you can eliminate irrelevant work, that's better.
For example, if you are applying for a User Interface design role, don't lump your fine art works in there. Put them in a separate category, just to show your range. But make UI work as the highlights and core. You don't want to dilute your skills.
Design is all about context, so why wouldn't you include them in your design portfolio? Basic info like the following are good context to have:
Describe your progress, and show your work-in-progress pictures. This gives an indication of how you are working as a designer than just a pixel pusher. The hiring manager wants to see your thinking process and your growth throughout your projects.
The quality of your process insights will differentiate you between a lowly paid vs highly paid designer. Or whether you get hired or not.
All the best, job seekers!