Here are some pictures from a trip to walk the GR20 in September 2015 with KE Adventure.

Full gallery (264 pictures).

GPS logs (.kmz - load into Google Earth).
Julien movie (22 sec.)

Sun 06 Sep
Arrive Bastia. Drive to Calvi.
Mon 07 Sep
Day 1: Calenzana to Refuge d'Ortu di u Piobbu.
Tue 08 Sep
Day 2: Refuge d'Ortu di u Piobbu to Refuge de Carrozzu.
Wed 09 Sep
Day 3: Refuge de Carrozzu to Haut Asco.
Thu 10 Sep
Day 4: Haut Asco to La Bergerie de Ballone. [Alternate route - Cirque de Solitude closed.]
Fri 11 Sep
Day 5: Castellu di Vergio.
Sat 12 Sep
Day 6: Castellu di Vergio to Refuge de Manganu.
Sun 13 Sep
Day 7: Refuge de Manganu to Refuge de l'Onda.
Mon 14 Sep
Day 8: Refuge de l'Onda to Monte D'Oro Gite.
Tue 15 Sep
Day 9: Monte D'Oro Gite to Col de Verde. [Alternate route - part of the original GR20.]
Wed 16 Sep
Day 10: Col de Verde to Cozzano.
Thu 17 Sep
Day 11: Cozzano to Crocce.
Fri 18 Sep
Day 12: Crocce to Bavella. [Low level route in the afternoon required by several group members.]
Sat 19 Sep
Day 13: Bavella to Conca. Drive to Bastia.
Sun 20 Sep
Depart Bastia.