You will need to find a suitable picture of your target first.

Facebook:

Downloading pictures on Facebook is easy.

Find a picture. Click on options and then download.

how to download pictures from facebook

Instagram:

To Download pictures from instagram, use this site:

Instagram Downloader 4 Pictures

As of now the picture software has some problems accessing private profiles.

 

Work-Around

If everything else fails, you can always press "print"  on  your keyboard to do a screenshot.

prtscn

Then open Windows Paint and press ctrl + v .

You should see your screenshot now. Just safe the picture as .jpeg and you are done.