numbering photos in a sequence
How can I export photos in a right sequence?
iMac (21.5-inch, Late 2013), OS X Yosemite (10.10.3), 8GB Ram, 1 Tb disk
If you want to number your photos on export, select them all at once, then use "File > Export > Export ..photos".
In the export dialog use the option "Filename > Sequential" and set a prefix.