One more thing that you could try is clearing and letting rebuild the “media storage”. It is some sort of index that keeps browsing through the files on your phone to build an index of all that contents. It seems that sometimes this media storage stops getting renewed, so newer files will not show up in it anymore.
Go to Settings > Apps > (touch the 3 point in the up-right corner) Show System processes (or something like that, I translate from french) > Media Storage > Storage* > Clear DATA. […] NOTE: It is important to let your fp rebuild his ‘library’ so wait at least 10min and check if you can load properly your pics on the phone (like usual)
Source:
If your photos still do not show when you connect to a computer, then feel free to contact Fairphone Support: