Contemporary images of 13th century Saracen mounted-crossbowmen are rare but they do exist.
An image of an Ayyubid mounted-crossbowman on a Glass Water-Flask, Syria, 1250-60. The trigger mechanism can be seen.
Other illustrations of Ayyubids on a Glass Water-Flask, British Museum 1869,0120.3
Another illustration from the Levant is The base of the Freer Canteen, with friezes of Christian or Muslim horsemen including two mounted-crossbowmen.
From a later period is Mamluk mounted crossbow & bow shooting in Kitsab al-makhzun jami` al-funun by ibn akhî hizâm - A Mamluk manual of military practice and horsemanship, Egypt or Syria, 1470
Mirror site
Ayyubid mounted-crossbowman on a Glass Water-Flask, Syria, 1250-60
Druzhina
Illustrations of Egyptian and Syrian Costume & Soldiers
