Data comes from the unitedstates/congress-legislators repo:
The file in static/legislators.csv comes from here:
https://theunitedstates.io/congress-legislators/legislators-current.csv
The unitedstates/images repo hosts public domain photos of legislators so that we don't have to have store them ourselves. We just have to follow this convention:
https://theunitedstates.io/images/congress/225x275 /[bioguide_id].jpg
Where [bioguide_id] is the bioguide identifier for a given congressmember. For example, Senator Dianne Feinstein has a Bioguide ID of F000062
Which means her photo can be found at:
https://theunitedstates.io/images/congress/225x275 /F000062.jpg