Interesting link from Hurriyet, a major Turkish Daily and reportedly the third most visited news website in Europe, probably due to the large number of immigrant Turks and Kurds in northern Europe. In any case it shows a large digital album of 100 year-old photographs.
Unfortunately they are not captioned. Photo #23 was particularly intriguing: six Turkish soldiers smiling at the camera next to a tent with an American flag hanging at the entrance. I am conjecturing that they are Turkish-American returnees. New York and New England received many ethnic Turks from the Balkans and Cyprus prior to WW-1.
Photo #40!!! Wow, that is a genuine old-school kanonisti. My back hurts just looking at that guy. Gallipoli probably and I bet that shell has either General Hamilton’s or Admiral de Robeck's name written on it in chalk.
Gallipoli is where Ataturk (Mustafa Kemal) made his bones. His face is undoubtedly in a photo of one of those groups of officers. A young Mulazim (Lieutenant) Tahsin Yazıcı was also at Gallipoli and may be in one of those pics. 35 years later he commanded the Turkish Brigade in Korea as part of the United Nations Command.
I used to associate Turkey during WW1 only with the Aussies at Gallipoli and Faisal’s Arab Revolt. But wait, not so fast: In eastern Turkey and the Caucasus the Ottomans fought battles at Ardahan, Sarikamish, Van, Koprukoy, Trabizon, Bitlis & Mus, Erzinca, Baku, Sardarapat, Kara-Killisse, and Bash-Arbaran. Circassian and Kurdish cavalry, Azeris, Persians, and German advisers fought alongside peasant Anatolian infantry (some Kurds fought for the Russkies too, they were not a monolithic bloc). The initial Russian advances (along with their Armenian and Assyrian allies) were most likely due to a priority Ottoman defense of Gallipoli. The Turks fought and won the the Battle of Ctesiphon and the Siege of Kut in Iraq. They beat Allenby in two of the three Battles of Gaza in Palestine but lost the third and the Battle of Megiddo. They stalemated the Brits in the Yemen. Turkish Navy ships in addition to contributing to the allied defeat at Gallipoli accompanied battlecruiser SMS Goeben (redesignated TCG Yavuz) on raids to Russian ports in the Black Sea.
Good reads on the subject are by Professor Edward J Erickson, former US Army Field Artillery Officer, and is now a professor of military history. He has written several books on Turkey and its history.
UPDATE: I have been scolded, and rightfully so, for not mentioning five other WW1 Fronts in which Ottoman troops served:
Galicia where the 19th and 20th Turkish Divisions were hastily sent after Austro Hungarian Forces melted during the Brusilov Offensive. The famous 19th Division had previously been commanded by Atataturk at Gallipoli. They fought alongside the German 55th and 1st (Reserve) Bavarian Divisions. (Note – This area is now mostly the Western Ukraine)
Romania where the 15th and 25th Turkish Divisions fought under von Mackensen against both Romanian and Russian troops.
Macedonia where two more Turkish Divisions (50th and 46th) reinforced the Bulgarians and fought against an Anglo-French Expeditionary Force. (Note – The Turks arrived there to much cheering by Khosovars and Albanians.)
Libya where the Turks armed and advised the Senussi guerrilla war against the Italians and also invaded the British in Egypt. They were reinforced with a single Turkish Infantry Battalion. (Note – The Senussis were a key anti-Gaddafi faction in the 2011 Libyan Civil War.)
Iraq/Persian border where a small Turkish detachment held off Russian attacks on Khanaqin. (Note - Khanaqin is just a short distance away from Jalawla where heavy fighting is going on today between Kurds and IS.)